Upgrade @metamask/subscription-controller to version 8.0.0

A new major version of `@metamask/subscription-controller`, 8.0.0, 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.

The issue names no files, tests, or entry points. Start by checking the project manifests and lockfiles to confirm whether @metamask/subscription-controller is present, then review the package's 8.0.0 release requirements and run the affected validation checks; done means the dependency is upgraded without regressions.

Written by the indexing model from the issue text.