Merge branch '456621-tailwind-box-shadows' into 'master'

Migrate box shadow utils to Tailwind

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/150023



Merged-by: Jose Ivan Vargas <jvargas@gitlab.com>
Approved-by: Jose Ivan Vargas <jvargas@gitlab.com>
Reviewed-by: Jose Ivan Vargas <jvargas@gitlab.com>
Co-authored-by: Paul Gascou-Vaillancourt <paul.gascvail@gmail.com>