…t tokens across chains for evm-scope specifically cp-7.76.0 (#29675)

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This PR fixes an app crash that occurs when the user clicks the
"unstake" button (ETH pooled-staking) when non-evm network is selected.

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CHANGELOG entry: fixed app crash occurring when user clicked
pooled-staking unstake button when non-evm network is selected.

Fixes: [MUSD-771: App Crash when user clicks pooled-staking "unstake"
button](https://consensyssoftware.atlassian.net/browse/MUSD-771)

```gherkin
Feature: Fix app crash when clicking "unstake" button (pooled-staking)

  Scenario: App crash fixed
    Given user has Staked ETH to unstake

    When user clicks "Tokens" section header on home screen
    And user selects non-EVM network (e.g. Tron) in network selector
    And user returns to home screen
    And user clicks Ethereum asset row
    And user clicks "unstake" button on Ethereum asset details screen

    Then user is redirected to unstake screen with keypad
    And the app does not crash
```

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- [x] I've followed [MetaMask Contributor
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- [ ] 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).

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<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Medium Risk**
> Medium risk because it changes how the unified multichain token
selector chooses the EVM address, which can affect token lists and Earn
flows across networks; however the change is localized and covered by
updated unit tests/mocks.
>
> **Overview**
> Fixes a crash/empty-balance issue when a non-EVM network is active by
making `selectAccountTokensAcrossChainsUnified` always derive EVM tokens
from the *EVM-scoped* account in the selected account group, rather than
whatever account is currently selected.
>
> Adds `selectAccountTokensAcrossChainsForEvmScope` (using
`selectSelectedInternalAccountByScope(EVM_SCOPE)` +
`selectAccountTokensAcrossChainsForAddress`) and updates
multichain/Earn-related tests to mock
`selectSelectedInternalAccountByScope` and the new EVM-token selector
signature.
>
> <sup>Reviewed by [Cursor Bugbot](https://cursor.com/bugbot) for commit
d5602d9. Bugbot is set up for automated
code reviews on this repo. Configure
[here](https://www.cursor.com/dashboard/bugbot).</sup>
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