mgr/dashboard: monitoring menu entry should indicate firing alerts

mgr/dashboard: monitoring menu entry should indicate firing alerts

Fixes: https://tracker.ceph.com/issues/43081
Signed-off-by: Volker Theile <vtheile@suse.com>
(cherry picked from commit f88fb46d680127963c0d04b797b5742ada6024b4)

Conflicts:
	src/pybind/mgr/dashboard/frontend/src/app/core/navigation/navigation/navigation.component.html
	src/pybind/mgr/dashboard/frontend/src/app/core/navigation/navigation/navigation.component.scss
	src/pybind/mgr/dashboard/frontend/src/app/core/navigation/navigation/navigation.component.spec.ts