Add type hints to `tests/rest/client` (#12072)

changelog.d/12072.misc

tests/rest/client/test_consent.py

tests/rest/client/test_device_lists.py

tests/rest/client/test_ephemeral_message.py

tests/rest/client/test_identity.py

tests/rest/client/test_keys.py

tests/rest/client/test_password_policy.py

tests/rest/client/test_power_levels.py

tests/rest/client/test_presence.py

tests/rest/client/test_room_batch.py

tests/rest/client/utils.py