Enhance config flow and tests for calendar_event integration

- Update comparison method selector to use dropdown mode in config flow.
- Modify binary sensor tests to include various matching criteria.
- Adjust setup tests to ensure correct calendar entity registration.

Author: andrew-codechimp

custom_components/calendar_event/config_flow.py

@@ -31,7 +31,9 @@
             CONF_COMPARISON_METHOD, default="contains"
         ): selector.SelectSelector(
             selector.SelectSelectorConfig(
-                options=_MATCHING_CRITERIA, translation_key=CONF_COMPARISON_METHOD
+                options=_MATCHING_CRITERIA,
+                mode="dropdown",
+                translation_key=CONF_COMPARISON_METHOD,
             ),
         ),
     }