Description of Problem

As described in the comments to this bug, Argo CD notifications does not currently support multiple replicas (and an RFE has been opened to support that). We should thus not allow Openshift GitOps users to put Argo CD in an unsupported configuration.

If users attempt to set >1 replicas on notification controller via ArgoCD CR, then OpenShift GitOps should log an error, and updated .status.conditions[ErrorOccurred] to with a a message that indicates the problem. Argo CD should not proceed further in reconciling the ArgoCD CR until the replica count is returned to a correct value.

Additional Info

NA

Problem Reproduction

• Install OpenShift GitOps (Any supported version) 
• Enable notifications in ArgoCD CR
• Increase the replicas of notifications-controller to 2 via ArgoCD CR