feat(account-tree-controller): add AccountsController:accountRenamed event handling

[mathieuartu]

Explanation

This PR adds support for handling AccountsController:accountRenamed events in AccountTreeController to maintain compatibility with both legacy account syncing and the multichain accounts state 1 implementation.

AccountTreeController now subscribes to and handles AccountsController:accountRenamed events. When an EVM account is renamed, the controller automatically updates the corresponding account group name if the group has a default name pattern ("Account X") but the account now has a custom name. This ensures that custom account names are reflected at the group level for better user experience.

This change maintains support for legacy account syncing flows that depend on programmatic account renames while ensuring AccountTreeController state remains consistent with account renames even though the UI doesn't use the tree structure yet in multichain state 1.

References

Fixes: https://consensyssoftware.atlassian.net/browse/MUL-521

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