feat: estimate gas batch action

[matthewwalsh0]

Explanation

Add TransactionController:estimateGasBatch messenger action to estimate gas for transactions batches.

Use in Relay quotes to more accurately estimate gas limit for source transaction batches, in addition to existing TransactionController:estimateGas messenger action for single source transactions.

References

Related to #23563

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've communicated my changes to consumers by updating changelogs for packages I've changed
• I've introduced breaking changes in this PR and have prepared draft pull requests for clients and consumer packages to resolve them

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Note

Introduce batch gas estimation (estimateGasBatch) in TransactionController and use it in Relay to compute buffered gas limits and drive submission (including optional EIP‑7702 gasLimit7702).

• Transaction Controller:
  • API: Add estimateGasBatch method and messenger action TransactionController:estimateGasBatch to estimate gas for batches (returns totalGasLimit and per-tx gasLimits).
  • Utils: Implement estimateGasBatch and update simulateGasBatch to return both total and per-transaction limits; support EIP-7702 batching and upgrade checks.
  • Batch Flow: Use totalGasLimit from simulation; accept optional gasLimit7702 in TransactionBatchRequest.
  • Types/Exports: Export new action type; add TransactionType.relayDeposit.
  • Tests: Add coverage for new action and gas batch logic.
• Transaction Pay (Relay):
  • Quotes: Estimate gas via messenger (estimateGas/estimateGasBatch), apply per-chain gasBuffer feature flag, and attach original.metamask.gasLimits to quotes.
  • Submit: Use provided gas limits; when a single limit is present for EIP-7702 batches, pass gasLimit7702; tag deposits as relayDeposit.
  • Feature Flags: Add getGasBuffer with default and per-chain overrides.
  • Tests/Changelog: Update tests and changelog accordingly.

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