feat: increase parallel count for atf runs (#16450)

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

.tekton/run-atf-tests-pull-request.yaml

@@ -52,7 +52,7 @@ spec:
     - name: aap-dev-component-source-name
       value: "controller"
     - name: pytest-number-of-parallel-processes
-      value: "2"
+      value: "6"
 
   workspaces:
     - name: workspace