Merge PR #40817 into master

Merge PR #40817 into master

* refs/pull/40817/head:
	mgr/MgrStandby: fix config observer
	mgr/MgrStandby: respawn if mgr_standby_modules changes
	qa/tasks/mgr/test_dashboard: skip test_standby if mgr_standby_modules=false
	qa/suites/rados/cephadm/smoke-*: use cephadm.wait_for_service
	qa/suites/rados/cephadm/smoke-singlehost: test --single-host-defaults
	cephadm: add --single-host-defaults option to bootstrap
	mgr/cephadm: allow mgr colo if mgr_standby_modules=false
	mgr/MgrStandby: add mgr_standby_modules option

Reviewed-by: Sebastian Wagner <swagner@suse.com>