mgr/dashboard: add telemetry activation notification

mgr/dashboard: add telemetry activation notification

The commit adds 2 different parts to show the
Telemetry activation notification in the dashboard:

1. The Telemetry activation notification component
   itself. It contains the definition of the
   notification panel.
2. The Telemetry notification service. The service
   is needed to be able to show/hide the
   notification from:
   * the component itself (e.g. when clicking the
     button button)
   * the Telemetry configuration component (when
     enabling/disabling Telemetry)
   * the navigation component (to set the css-
     classes accordingly)

Fixes: https://tracker.ceph.com/issues/45464
Signed-off-by: Tatjana Dehler <tdehler@suse.com>
(cherry picked from commit f7e457952ba5780b4b7fc3a1e4290c02d4e5d70d)

Conflicts:
	src/pybind/mgr/dashboard/frontend/src/app/ceph/cluster/telemetry/telemetry.component.ts
	A form loading directive has been introduced in master: https://github.com/ceph/ceph/pull/34746

	src/pybind/mgr/dashboard/frontend/src/app/core/navigation/navigation/navigation.component.spec.ts
	The test configuration has been improved in master: https://github.com/ceph/ceph/pull/34965

	src/pybind/mgr/dashboard/frontend/src/app/shared/components/telemetry-notification/telemetry-notification.component.html
	src/pybind/mgr/dashboard/frontend/src/app/shared/components/telemetry-notification/telemetry-notification.component.spec.ts
	The alert component has been migrated from ngx-bootstrap to ng-boostrap in master: https://github.com/ceph/ceph/pull/35297
	TestBed.get has been replaced by TestBed.inject in master: https://github.com/ceph/ceph/pull/34934

	src/pybind/mgr/dashboard/frontend/src/app/shared/services/telemetry-notification.service.spec.ts
	TestBed.get has been replaced by TestBed.inject in master: https://github.com/ceph/ceph/pull/34934

The backport contains one commit less (39a26ae4b2a1b154c88a414c4abee1c04808effa
is missing) than the original pull request because the migration from alert to
ngb-alert (https://github.com/ceph/ceph/pull/35297) has not been backported.