Extends GasFeePoller to update gas properties for unapproved transaction batches

[vinistevam]

Explanation

This PR extends the GasFeePoller to track/update gas properties for unapproved transactionBatches.

Changes

The GasFeePoller now:

• Detects unapproved transactionBatches via #getUnapprovedTransactionBatches.
• Fetches gas estimates using DefaultGasFeeFlow.
• Emits transaction-batch-updated events with updated gasFeeEstimates.

Updates are applied to the TransactionBatchMeta for each batch, mirroring the behaviour already in place for single transactions.
This enhancement ensures that unapproved transaction batches receive timely gas updates similar to individual transactions, improving consistency across transaction types.

References

Fixes https://github.com/MetaMask/MetaMask-planning/issues/5090

Changelog

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, highlighting breaking changes as necessary
• I've prepared draft pull requests for clients and consumer packages to resolve any breaking changes

[OGPoyraz]

I maybe missing the context - why we are estimating only the first transaction?

Shouldn't we estimate all nested transactions and return all gas estimates and then UI calculates them all and show as final network fee estimate?

[vinistevam]

So, for now, we ultimately need the gasFee on the batch to render in the confirmation. That gives us two alternatives for MVP estimate for the first transaction or estimate all transactions (it can be X txs) and pick the highest one. However, this can be tricky for Linea, for example, their RPC will fail if a transaction requires a previous transaction, like a token approval.

In the end, for the batch, we are using the simplest case, only getting a network level estimate (via the DefaultGasFeeFlow).

[matthewwalsh0]

Minor, you only need to do or the other, either update the draft directly, or return a new object.

[vinistevam]

Good point, changed to use only one approach.