Remove unused enum from Microsoft.Resources/changes (#18788)

* Update changes.json

* Prettier

Author: dhu5432

specification/resources/resource-manager/Microsoft.Resources/stable/2022-05-01/changes.json

@@ -308,8 +308,7 @@
           "readOnly": true,
           "enum": [
             "User",
-            "System",
-            "Create"
+            "System"
           ],
           "x-ms-enum": {
             "name": "ChangeCategory",