use approvalType.TransactionBatch

[vinistevam]

Explanation

This PR aims to change the hardcoded transaction_batch to use the ApprovalType.TransactionBatch from Controller utils, and some cleanup in unit tests.

References

Fixeshttps://github.com/MetaMask/MetaMask-planning/issues/5143

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