Merge branch '391095-vue3-migration-app_spec' into 'master'

Removes spying on methods from app_spec

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/127940



Merged-by: Anna Vovchenko <avovchenko@gitlab.com>
Approved-by: Samantha Ming <sming@gitlab.com>
Approved-by: Anna Vovchenko <avovchenko@gitlab.com>
Co-authored-by: Artur Fedorov <afedorov@gitlab.com>