Merge branch '433035-status-checks-update-model-update-service' into 'master'

Add shared_secret to External status check update_service

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/160542



Merged-by: Marcos Rocha <mrocha@gitlab.com>
Approved-by: Alan (Maciej) Paruszewski <mparuszewski@gitlab.com>
Approved-by: Marcos Rocha <mrocha@gitlab.com>
Co-authored-by: Artur Fedorov <afedorov@gitlab.com>