feat: simplify transaction timeout (#7464)

## Explanation

Simplify the transaction timeout mechanism to not count attempts, but
instead check the time since submit, or when the transaction was last
seen on the network.

Calculates the timeout duration using the `blockTime` from the
accelerated polling feature flags.

## References

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## Checklist

- [x] I've updated the test suite for new or updated code as appropriate
- [x] I've updated documentation (JSDoc, Markdown, etc.) for new or
updated code as appropriate
- [x] I've communicated my changes to consumers by [updating changelogs
for packages I've
changed](https://github.com/MetaMask/core/tree/main/docs/contributing.md#updating-changelogs)
- [x] I've introduced [breaking
changes](https://github.com/MetaMask/core/tree/main/docs/breaking-changes.md)
in this PR and have prepared draft pull requests for clients and
consumer packages to resolve them


<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Replaces attempt-based pending transaction timeout with a time-based
check (since submit or last seen), using `blockTime * threshold`, and
updates feature flags/tests accordingly.
> 
> - **Transaction logic (`src/helpers/PendingTransactionTracker.ts`)**:
> - Replace attempt counter with time-based timeout using
`submittedTime` or last seen timestamp; derive timeout from
`getAcceleratedPollingParams().blockTime * threshold`.
> - Track last-seen times per `hash` via `#lastSeenTimestampByHash`;
reset when tx is seen and clear on confirm/fail/drop.
> - Use new `#cleanTransaction` to clear force-poll and last-seen state;
remove timeout counter usage.
> - **Feature flags (`src/utils/feature-flags.ts`)**:
> - Add default `blockTime` (12s) and include optional `blockTime` in
`acceleratedPolling.perChainConfig`.
> - Update `getAcceleratedPollingParams` to return `{ blockTime,
countMax, intervalMs }`.
> - **Tests**:
> - Update `PendingTransactionTracker.test.ts` to use fake timers and
validate time-based timeout, last-seen resets, and threshold behavior.
> - Extend `feature-flags.test.ts` to assert `blockTime` defaults,
per-chain overrides, and merging.
> - **Changelog**:
> - Note timeout change to time-based and usage of
`acceleratedPolling.blockTime`.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
e776a73. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: matthewwalsh0

packages/transaction-controller/CHANGELOG.md

@@ -9,6 +9,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+- Update transaction timeout to check time since submission or when transaction was last seen on network ([#7464](https://github.com/MetaMask/core/pull/7464))
+  - Uses `blockTime` from `acceleratedPolling` feature flag.
 - Deprecate `history` and `sendFlowHistory` properties from `TransactionMeta` and `TransactionController` options ([#7326](https://github.com/MetaMask/core/pull/7326))
 - Bump `@metamask/remote-feature-flag-controller` from `^3.0.0` to `^3.1.0` ([#7519](https://github.com/MetaMask/core/pull/7519))
 - Bump `@metamask/network-controller` from `^27.0.0` to `^27.1.0` ([#7534](https://github.com/MetaMask/core/pull/7534))