Merge branch '388129-ui-update' into 'master'

Adjust Branch Rules Settings UI to new designs

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/148696



Merged-by: Jacques Erasmus <jerasmus@gitlab.com>
Approved-by: Michael Le <mle@gitlab.com>
Approved-by: Tomas Vik <tvik@gitlab.com>
Approved-by: Jacques Erasmus <jerasmus@gitlab.com>
Reviewed-by: Jacques Erasmus <jerasmus@gitlab.com>
Co-authored-by: psjakubowska <psedlak-jakubowska@gitlab.com>