Add feature_category declaration

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/160781



Merged-by: Alper Akgun <aakgun@gitlab.com>
Approved-by: Tetiana Chupryna <tchupryna@gitlab.com>
Approved-by: Alper Akgun <aakgun@gitlab.com>
Co-authored-by: Kerri Miller <kerrizor@kerrizor.com>