Fix up unit tests (#10723)

These were broken in an incorrect merge of GHSA-jj53-8fmw-f2w2 (cb35df94)

changelog.d/10723.bugfix

+Fix unauthorised exposure of room metadata to communities.

tests/rest/client/v2_alpha/test_groups.py

-from synapse.rest.client.v1 import room
-from synapse.rest.client.v2_alpha import groups
+# Copyright 2021 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from synapse.rest.client import groups, room
 
 from tests import unittest
 from tests.unittest import override_config