mgr/dashboard: redirect to original URL after successful login

mgr/dashboard: redirect to original URL after successful login

Fixes: https://tracker.ceph.com/issues/45067
Signed-off-by: Avan Thakkar <athakkar@redhat.com>
(cherry picked from commit b5359a155c6ff7e92ab6c6ed16f7ff9fc76c76ea)
(cherry picked from commit 330c75cb511d61306a8841973f2b18e17893c555)

Conflicts:
	src/pybind/mgr/dashboard/frontend/src/app/shared/services/auth-guard.service.spec.ts
	src/pybind/mgr/dashboard/frontend/src/app/core/auth/login/login.component.ts
  - Adapted changes in these files to nautilus code.