afform_mock - Simplify; use auto-requires

mock/ang/testAfform.aff.json

 {
   "server_route": "civicrm/test-afform",
-  "title": "This is a test",
-  "requires": [
-    "af", "afBlock", "afField", "afCore"
-  ]
+  "title": "This is a test"
 }