Merge branch '506542-prevent-all-protected-branches-squash-option' into 'master'

Hide squash options for All protected branches

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/183337



Merged-by: Paulina Sedlak-Jakubowska <psedlak-jakubowska@gitlab.com>
Approved-by: Paulina Sedlak-Jakubowska <psedlak-jakubowska@gitlab.com>
Co-authored-by: Jacques <jerasmus@gitlab.com>