Revert "tests: disable test_mgr_dashboard_is_listening"
Revert "tests: disable test_mgr_dashboard_is_listening"

This reverts commit 2e19d1705efa8ef247eecb540357195d5142da77.

A new build of ceph@master including the fix is available so
this is not needed anymore.

Signed-off-by: Guillaume Abrioux <30a9df5a0293a6108675377fa1673f7aa713f915@redhat.com>

ceph/ceph-ansible,ceph/ceph-ansible