…issing or non-positive network fee data (#30313)

## **Description**
This pull request improves how the Bridge UI handles and displays cases
where the network fee is unavailable, especially for Bitcoin (BTC)
bridges. It introduces a new hook to detect unavailable network fees,
updates the logic for disabling/enabling the confirm button, and adjusts
messaging and analytics accordingly. The changes also include
comprehensive tests for these scenarios.

**Key changes:**

**1. Handling Network Fee Unavailability in the UI**
- Added the `useIsNetworkFeeUnavailable` hook to detect when the network
fee (especially for BTC) is unavailable and integrated it into both
`BridgeView` and `SwapsConfirmButton` components. This disables the
confirm button and updates the label to "Insufficient funds" when the
fee is unavailable.

**2. Analytics and Event Tracking**
- Updated the `useBridgeQuoteEvents` hook and its consumers to track
when the network fee is unavailable, emitting a new
`network_fee_unavailable` warning instead of the generic insufficient
gas warning.

**3. Gas Fee Calculation Logic**
- Modified `useHasSufficientGas` to use `totalNetworkFee.amount` for BTC
quotes instead of `gasFee.effective.amount`, ensuring correct balance
validation for Bitcoin transactions.

**4. Testing and Coverage**
- Added and updated tests for both the UI and hooks to cover scenarios
where the BTC network fee is unavailable, ensuring proper button states,
messaging, and analytics events. This includes new test cases for
`SwapsConfirmButton` and `useBridgeQuoteEvents`, and additional
BTC-specific tests for `useHasSufficientGas`.

These updates ensure that users are clearly informed when a bridge
transaction cannot proceed due to unavailable network fees, especially
for Bitcoin, and that analytics accurately reflect this state.

## **Changelog**

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`CHANGELOG entry: Added a new tab for users to see their NFTs`
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CHANGELOG entry: fixed BTC quote when BTC quote has missing or
non-positive network fee data

## **Related issues**

Fixes: Bridging BTC is failing at the transaction crafting in certain
cases

## **Manual testing steps**

BTC quote with unavailable fee

1. Open the Bridge/Swap flow.
2. Select BTC as the source token and ETH as the destination token.
3. Enter an amount that can produce a BTC quote.
4. Simulate or reproduce a quote where the BTC network fee is 0 or
unavailable.
5. Confirm the CTA shows Insufficient funds.

## **Screenshots/Recordings**

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before and after of your change. -->

### **Before**

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### **After**

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## **Pre-merge author checklist**

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- [ ] I've followed [MetaMask Contributor
Docs](https://github.com/MetaMask/contributor-docs) and [MetaMask Mobile
Coding
Standards](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/CODING_GUIDELINES.md).
- [ ] I've completed the PR template to the best of my ability
- [ ] I've included tests if applicable
- [ ] I've documented my code using [JSDoc](https://jsdoc.app/) format
if applicable
- [ ] I've applied the right labels on the PR (see [labeling
guidelines](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/LABELING_GUIDELINES.md)).
Not required for external contributors.

#### Performance checks (if applicable)

- [ ] I've tested on Android
  - Ideally on a mid-range device; emulator is acceptable
- [ ] I've tested with a power user scenario
- Use these [power-user
SRPs](https://consensyssoftware.atlassian.net/wiki/spaces/TL1/pages/edit-v2/401401446401?draftShareId=9d77e1e1-4bdc-4be1-9ebb-ccd916988d93)
to import wallets with many accounts and tokens
- [ ] I've instrumented key operations with Sentry traces for production
performance metrics
- See [`trace()`](/app/util/trace.ts) for usage and
[`addToken`](/app/components/Views/AddAsset/components/AddCustomToken/AddCustomToken.tsx#L274)
for an example

For performance guidelines and tooling, see the [Performance
Guide](https://consensyssoftware.atlassian.net/wiki/spaces/TL1/pages/400085549067/Performance+Guide+for+Engineers).

## **Pre-merge reviewer checklist**

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Reviewer checklist items follow the same semantics as the author
checklist: an
unchecked box is ambiguous, a checked box means the reviewer consciously
assessed that responsibility. See `docs/readme/ready-for-review.md`.
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- [ ] I've manually tested the PR (e.g. pull and build branch, run the
app, test code being changed).
- [ ] I confirm that this PR addresses all acceptance criteria described
in the ticket it closes and includes the necessary testing evidence such
as recordings and or screenshots.



<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Medium Risk**
> Updates bridge confirmation disablement, labeling, and analytics
around fee/gas validation, which can block submissions and alter event
warnings; impact is mostly limited to BTC and UI state handling but
affects core swap/bridge CTA logic.
> 
> **Overview**
> **Improves BTC quote handling when network fee data is
missing/invalid.** Adds `useIsNetworkFeeUnavailable` to detect BTC
quotes with missing, non-finite, or non-positive
`totalNetworkFee.amount`, and uses it to disable submission and show
*Insufficient funds* (instead of *Insufficient gas*) in `BridgeView`,
`SwapsConfirmButton`, and Quick Buy.
> 
> **Adjusts fee validation + analytics.** `useHasSufficientGas` now
prefers `totalNetworkFee.amount` for BTC when checking gas sufficiency,
and `useBridgeQuoteEvents` emits a new `network_fee_unavailable` warning
(taking precedence over insufficient gas).
> 
> **Expands test coverage.** Adds/updates unit tests to cover BTC
network-fee-unavailable cases across confirm button states, “Get new
quote” enablement, quote warnings, Quick Buy button errors, and BTC gas
validation.
> 
> <sup>Reviewed by [Cursor Bugbot](https://cursor.com/bugbot) for commit
30e4c63. Bugbot is set up for automated
code reviews on this repo. Configure
[here](https://www.cursor.com/dashboard/bugbot).</sup>
<!-- /CURSOR_SUMMARY -->