Description of problem (please be detailed as possible and provide log
snippests):
CephMonLowNumber alert is raised only when metrics exporter pod is restarted 

On a vmware cluster where more than five failure domains are added, CephMonLowNumberalert is not shown automatically, metrics exporter pod needs to be restarted to get alerts

Version of all relevant components (if applicable):
OCP 4.15 and ODF 4.15.0-122

Does this issue impact your ability to continue to work with the product
(please explain in detail what is the user impact)?
NA

Is there any workaround available to the best of your knowledge?
Restart metrics pod to get alerts
Rate from 1 - 5 the complexity of the scenario you performed that caused this
bug (1 - very simple, 5 - very complex)?
1

Can this issue reproducible?
Yes

Can this issue reproduce from the UI?
Yes

If this is a regression, please provide more details to justify this:
NA

Steps to Reproduce:
1.Install a 3master 6 worker node cluster
2.Label the worker nodes in different failure domains using command "oc label node compute-2 failure-domain.beta.kubernetes.io/zone=rack-2 --overwrite=true"
3. Wait for the "CephMonLowNumber" alert to be raised 


Actual results:
Alert is raised only if metrics pod is restarted

Expected results:
Whenever failure domain count reaches above 5, alert should be raised automatically

Additional info: