ci: do not leave testing comments on merged PRs
ci: do not leave testing comments on merged PRs

A PR with status `github.event.pull_request.merged == true` does not
need to be tested again.

Signed-off-by: Niels de Vos <7bda0c0ee7f47171cc808e9e60292cbc5d8140dd@redhat.com>

ceph/ceph-csi,ceph/ceph-csi,ceph/ceph-csi,ceph/ceph-csi