Merge branch '517578-remove-gitlab-vendor-option-from-feature-settings-ui' into 'master'

Remove 'GitLab AI Vendor' option from feature settings UI

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/180662



Merged-by: David Pisek <dpisek@gitlab.com>
Approved-by: Eduardo Bonet <ebonet@gitlab.com>
Approved-by: Susie Bitters <sbitters@gitlab.com>
Approved-by: David Pisek <dpisek@gitlab.com>
Co-authored-by: Julie Huang <julhuang@gitlab.com>