Upgrade @metamask/account-tree-controller to version 2.0.0

A new major version of `@metamask/account-tree-controller`, 2.0.0, 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.

Start by searching the repository for references to @metamask/account-tree-controller and checking whether the package is present. Review the 2.0.0 release changes before updating it, then run the existing project checks to identify compatibility issues. Done means the project uses the new version and its checks pass.

Written by the indexing model from the issue text.