Improve tests for Airly integration (#38357)

* Add tests

* More tests

* Add PARALLEL_UPDATES

* Change Quality scale to platinum

* Change PARALLEL_UPDATES value

homeassistant/components/airly/air_quality.py

@@ -31,6 +31,8 @@ LABEL_PM_2_5_PERCENT = f"{ATTR_PM_2_5}_percent_of_limit"
 LABEL_PM_10_LIMIT = f"{ATTR_PM_10}_limit"
 LABEL_PM_10_PERCENT = f"{ATTR_PM_10}_percent_of_limit"
 
+PARALLEL_UPDATES = 1
+
 
 async def async_setup_entry(hass, config_entry, async_add_entities):
     """Set up Airly air_quality entity based on a config entry."""