…-chain nonce for EIP-7702 authorization list (#30297)

## **Description**

When building the EIP-7702 authorization list for a Pay delegation
transaction, the nonce was previously read from `NonceLock.nextNonce` —
the value computed by the nonce tracker, which accounts for
locally-pending transactions the Relay has no visibility into. This
could produce a nonce ahead of the true on-chain state, causing the
Relay to reject the authorization as invalid.

The fix reads `NonceLock.nonceDetails.params.nextNetworkNonce` instead —
the raw `eth_getTransactionCount` result that the nonce tracker already
fetches internally. This gives the committed on-chain nonce the Relay
needs to verify the authorization signature, without introducing a
separate provider call or adding a new Engine dependency.

## **Changelog**

CHANGELOG entry: null

## **Related issues**

Related to: #30798 

## **Manual testing steps**

```gherkin
Feature: EIP-7702 Pay delegation transaction

  Scenario: user submits a Pay transaction requiring EIP-7702 upgrade
    Given the account has not yet been delegated (not upgraded to EIP-7702)
    And the account has locally-pending transactions in the queue

    When user initiates a Pay transaction and confirms
    Then the authorization list is signed with the correct on-chain nonce
    And the transaction submits successfully via Relay
```

## **Screenshots/Recordings**

### **Before**

<!-- N/A — no UI change -->

### **After**

<!-- N/A — no UI change -->

## **Pre-merge author checklist**

- [x] 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).
- [x] I've completed the PR template to the best of my ability
- [x] I've included tests if applicable
- [x] I've documented my code using [JSDoc](https://jsdoc.app/) format
if applicable
- [x] 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

## **Pre-merge reviewer checklist**

- [ ] 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**
> Changes nonce selection for EIP-7702 authorization signing in Pay
flows; wrong nonce would break Relay submission but scope is limited to
delegation authorization building.
> 
> **Overview**
> **EIP-7702 Pay delegation** now signs the authorization list with the
**committed on-chain nonce**
(`nonceLock.nonceDetails.params.nextNetworkNonce`) instead of the nonce
tracker’s **`nextNonce`**, which can include locally pending txs the
Relay cannot see.
> 
> Tests were updated to mock `networkClientId` on transaction meta and
to return the new nonce lock shape so
`KeyringController:signEip7702Authorization` still receives the expected
nonce.
> 
> <sup>Reviewed by [Cursor Bugbot](https://cursor.com/bugbot) for commit
7d0387b. Bugbot is set up for automated
code reviews on this repo. Configure
[here](https://www.cursor.com/dashboard/bugbot).</sup>
<!-- /CURSOR_SUMMARY -->