We must not create the namespace nor operator group when gitOpsSubNamespace is empty or null

Otherwise the old operator with the new chart will try and actually push
the namespace + operatorgroup policies with names like this:

  - complianceType: mustonlyhave
    objectDefinition:
      apiVersion: v1
      kind: Namespace
      metadata: {}
  - complianceType: mustonlyhave
    objectDefinition:
      apiVersion: operators.coreos.com/v1
      kind: OperatorGroup
      metadata:
        name: -operator-group

And they will never be compliant

Author: mbaldessari

templates/policies/ocp-gitops-policy.yaml

@@ -53,7 +53,7 @@ spec:
                   namespace: openshift-gitops
                   labels:
                     config.openshift.io/inject-trusted-cabundle: 'true'
-            {{- if ne $.Values.global.gitOpsSubNamespace "openshift-operators" }}
+            {{- if and $.Values.global.gitOpsSubNamespace (ne $.Values.global.gitOpsSubNamespace "openshift-operators") }}
             - complianceType: mustonlyhave
               objectDefinition:
                 apiVersion: v1

tests/gitops_sub_namespace_test.yaml

@@ -137,6 +137,44 @@ tests:
           path: spec.policy-templates[0].objectDefinition.spec.object-templates
           count: 2 # Just subscription and configmap
 
+  - it: should not create operatorgroup nor namespace object-template when gitOpsSubNamespace is set to null
+    set:
+      global:
+        gitOpsSubNamespace: null
+      clusterGroup:
+        managedClusterGroups:
+          region-one:
+            name: region-one
+            acmlabels:
+              - name: clusterGroup
+                value: region-one
+    asserts:
+      - documentSelector:
+          path: metadata.name
+          value: region-one-gitops-policy
+        lengthEqual:
+          path: spec.policy-templates[0].objectDefinition.spec.object-templates
+          count: 2 # Just subscription and configmap
+
+  - it: should not create operatorgroup nor namespace object-template when gitOpsSubNamespace is set to empty
+    set:
+      global:
+        gitOpsSubNamespace: ''
+      clusterGroup:
+        managedClusterGroups:
+          region-one:
+            name: region-one
+            acmlabels:
+              - name: clusterGroup
+                value: region-one
+    asserts:
+      - documentSelector:
+          path: metadata.name
+          value: region-one-gitops-policy
+        lengthEqual:
+          path: spec.policy-templates[0].objectDefinition.spec.object-templates
+          count: 2 # Just subscription and configmap
+
   - it: should use gitOpsSubNamespace as subscription namespace when set
     set:
       global: