mgr/dashboard: expose more grafana configs in service form

mgr/dashboard: expose more grafana configs in service form

Show the grafana_port and initial_admin_password in the form but disable
the password field in the edit option

Fixes: https://tracker.ceph.com/issues/58016
Signed-off-by: Nizamudeen A <nia@redhat.com>
(cherry picked from commit 6987191377e5ca623563ae851d87e0961416e3f4)

 Conflicts:
	src/pybind/mgr/dashboard/frontend/src/app/ceph/cluster/services/service-form/service-form.component.ts
  - accept the current change and only apply the `case 'grafana'` in the
    PR.