Upgrade @metamask/account-tree-controller to version 7.0.0

A new major version of `@metamask/account-tree-controller`, 7.0.0, is now available. This issue has been assigned to you and your team because you code-own this package in the `core` repo. If this package is present in this project, please prioritize upgrading it soon to unblock new features and bugfixes.

Search the repository's package manifests for @metamask/account-tree-controller and confirm whether this project uses it. Update the dependency to version 7.0.0, then run the relevant existing checks for the extension; done means the package is upgraded without breaking those checks.

Written by the indexing model from the issue text.