fix: filter out replicas from nodeToClusters map (#1194)

We have found that using HasLabels and MatchingLabels in the same Kubernetes List call leads
to only one of them being applied. See kubernetes-sigs/controller-runtime#2098

This patch fixes one occurrence of this double usage in the operator code, 
avoiding some unneeded reconciliation cycles.

Signed-off-by: Jaime Silvela <jaime.silvela@enterprisedb.com>

controllers/cluster_controller.go

@@ -1098,8 +1098,10 @@ func (r *ClusterReconciler) mapNodeToClusters(ctx context.Context) handler.MapFu
 		// get all the pods handled by the operator on that node
 		err := r.List(ctx, &childPods,
 			client.MatchingFields{".spec.nodeName": node.Name},
-			client.MatchingLabels{specs.ClusterRoleLabelName: specs.ClusterRoleLabelPrimary},
-			client.HasLabels{utils.ClusterLabelName},
+			client.MatchingLabels{
+				specs.ClusterRoleLabelName: specs.ClusterRoleLabelPrimary,
+				utils.PodRoleLabelName:     string(utils.PodRoleInstance),
+			},
 		)
 		if err != nil {
 			log.FromContext(ctx).Error(err, "while getting primary instances for node")