Staging-53

What's Changed

• Change "Add user" to "Add a domain manager" by @michelle-rago in #1761
• Issue 1489: Reduce email sends to first-time transition for the applicable transitions by @rachidatecs in #1749
• (Quick fix) Ticket #1265: Contact success message correction by @zandercymatics in #1757
• Issue #1127: divorce health check from dependence on identity provider by @dave-kennedy-ecs in #1747
• (On getgov-backup) Ticket #1411: make statuses more meaningful by @zandercymatics in #1722
• Issue #1751: Handling of OIDC outages (during startup and during user logins) by @dave-kennedy-ecs in #1759

Full Changelog: staging-52...staging-53