Config flow tests: update tests for HA 2025.3

- add empty subentries placeholder to allow tests to pass against HA 2025.3
- bump required test framework version to ensure tests are carried out against that version.

requirements-dev.txt

@@ -1,6 +1,6 @@
 fuzzywuzzy
 levenshtein
-pytest-homeassistant-custom-component>=0.13.201
+pytest-homeassistant-custom-component>=0.13.221
 pytest
 pytest-asyncio
 pytest-cov

tests/test_config_flow.py

@@ -513,6 +513,7 @@ async def test_flow_choose_entities_creates_config_entry(hass, bypass_setup):
             "description": None,
             "description_placeholders": None,
             "result": ANY,
+            "subentries": (),
             "options": {},
             "data": {
                 CONF_DEVICE_ID: "deviceid",