mgr/dashboard: fix "NullInjectorError: No provider for I18n
Although I am not sure what's the root cause of this but this seems to
fix the test failure. I don't know if this is caused by the differnce in
angular versions between master and octopus but I still don't understand
why it didn't catch in the recent PR to this file (https://github.com/ceph/ceph/pull/44763)
Fixes: https://tracker.ceph.com/issues/55011 Signed-off-by: Nizamudeen A <nia@redhat.com>