Description of problem:

The data of Prometheus and Alertmanager get lost if
 - CMO's persistence is configured using prefix as described in doc
 - install community Prometheus Oprator


Version-Release number of selected component (if applicable):


How reproducible:


Steps to Reproduce:
1.Install old OCP (4.3, 4.4 or 4.5.x) - it installs CMO at the same time
2.Configure persistence of CMO's Prometheus and Alertmanager using prefix (in the ConfigMap 'cluster-monitoring-config'
3.Install community Prometheus Operator (into another namespace like 'monitoring'
4.Upgrade OCP to newer (4.4, 4.5.y)


Actual results:
Data lost


Expected results:
Data is kept


Additional info:
The root cause is CMO and community PO are both using the same (fully qualified) name for CRDs; *.monitoring.coreos.com

Step #2 creates PVCs with prefix, but step #3 produces another set of PVCs without prefix because CRDs like 'prometheuses.monitoring.coreos.com' are overwritten by community PO.

Step #4 reverts CRDs and PVCs with prefix are used again, but from users view point, recent metrics are not shown in Grafana.