Fix failing test

(cherry picked from commit 6459111)

Author: Hathoute

deps/rabbitmq_auth_backend_oauth2/test/config_schema_SUITE_data/rabbitmq_auth_backend_oauth2.snippets

@@ -101,7 +101,7 @@
                   {id, <<"rabbitmq-operations">>}
                 ],
                 <<"rabbitmq-customers">> => [
-                  {additional_scopes_key, <<"roles">>},
+                  {extra_scopes_source, <<"roles">>},
                   {id, <<"rabbitmq-customers">>}
                 ]
               }