Fix federation mapping role jsonschema

additionalProperties attribute must be located on the level of "type"
and not inside "properties"
(https://json-schema.org/understanding-json-schema/reference/object#additional-properties).
Sadly this is not violating schema validation, but is wrong and hurts
any reasonable processing of the schema.

Change-Id: Ib537f1dd33dd3f3dc8909873dffc37980d04b4db

keystone/federation/utils.py

@@ -50,8 +50,8 @@ ROLE_PROPERTIES = {
             "name": {
                 "type": "string"
             },
-            "additionalProperties": False
-        }
+        },
+        "additionalProperties": False
     }
 }