Merge branch 'ph/fixMRActionsNotVisibleOnDiffs' into 'master'

Fixes the merge request actions dropdown not being rendered on diffs tab

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/125571



Merged-by: Natalia Tepluhina <ntepluhina@gitlab.com>
Approved-by: Natalia Tepluhina <ntepluhina@gitlab.com>
Co-authored-by: Phil Hughes <me@iamphill.com>