Better message in the CMO degraded/unavailable conditions when alertmanager can't be scheduled

Better message in the CMO degraded/unavailable conditions when alertmanager pods can't be scheduled 

4.12.0-0.nightly-2022-08-24-053339

always

1. Configure alertmanager with an invalid volume claim template (unknown storage class for instance):
apiVersion: v1
kind: ConfigMap
metadata:
  name: cluster-monitoring-config
  namespace: openshift-monitoring
data:
  config.yaml: |
    alertmanagerMain:
      volumeClaimTemplate:
        metadata:
          name: monitorpvc
        spec:
          storageClassName: foo
          volumeMode: Filesystem
          resources:
            requests:
              storage: 1Gi
2. Wait for CMO to go degraded

% oc -n openshift-monitoring describe pod alertmanager-main-0 |tail -n 10
QoS Class:                   Burstable
Node-Selectors:              kubernetes.io/os=linux
Tolerations:                 node.kubernetes.io/memory-pressure:NoSchedule op=Exists
                             node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
                             node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
  Type     Reason            Age   From               Message
  ----     ------            ----  ----               -------
  Warning  FailedScheduling  13m   default-scheduler  0/6 nodes are available: 6 pod has unbound immediate PersistentVolumeClaims. preemption: 0/6 nodes are available: 6 Preemption is not helpful for scheduling.
  Warning  FailedScheduling  13m   default-scheduler  0/6 nodes are available: 6 pod has unbound immediate PersistentVolumeClaims. preemption: 0/6 nodes are available: 6 Preemption is not helpful for scheduling.
% oc get co monitoring -o jsonpath='{.status.conditions}' | jq 'map(select(.type=="Degraded" or .type=="Available"))'
[
  {
    "lastTransitionTime": "2022-08-25T08:51:55Z",
    "reason": "AsExpected",
    "status": "True",
    "type": "Available"
  },
  {
    "lastTransitionTime": "2022-08-25T08:51:55Z",
    "message": "waiting for Alertmanager object changes failed: waiting for Alertmanager openshift-monitoring/main: expected 2 replicas, got 0 updated replicas",
    "reason": "UpdatingAlertmanagerFailed",
    "status": "True",
    "type": "Degraded"
  }
]

CMO should surface a better explanation as to why the pods aren't in the desired state. The available status should be false

The fix of the following bug makes co monitoring reflect status of prometheus pos/prometheus operator now, the co monitoring failed to reflect status of alermanager pod
https://bugzilla.redhat.com/show_bug.cgi?id=2043518