Exporter service created by rook operator contains the following labels:
`app=rook-ceph-exporter,rook_cluster=<cluster-name>`
Label `ceph_daemon_id=exporter` is not there and therefore the service
monitor selector can not discover the exporter service.
This fix removes the `ceph_daemon_id=exporter` label from the exporter
service monitor selector.
Signed-off-by: Matej Feder <matej.feder@dnation.cloud>