Merge branch 'master' of https://github.com/alphagov/notifications-admin into vb-callback-admin

Some content change
Refractor api_integration to api_keys to reduce git difference.

tests/app/main/test_validators.py

@@ -149,7 +149,7 @@ def test_for_commas_in_placeholders(
 ):
     with pytest.raises(ValidationError) as error:
         NoCommasInPlaceHolders()(None, _gen_mock_field('Hello ((name,date))'))
-    assert str(error.value) == 'You can’t have commas in your fields'
+    assert str(error.value) == 'You can’t put commas between double brackets'
     NoCommasInPlaceHolders()(None, _gen_mock_field('Hello ((name))'))