Improve airq handling of DeviceInfo (#90232)

* Reduce data sharing between ConfigFlow and DataUpdateCoordinator

Instead of fetching device information from the device once in
`ConfigFlow` and then piping it through in `ConfigEntry.data`,
only use as much as needed in `ConfigFlow.async_step_user`, then fetch
again in `AirQCoordinator._async_update_data` if a key is missing.

Additionally, factor `AirQCoordinator` out into a sumbodule.

Add a simple test for `AirQCoordinator.device_info` update.

Positive side effect: `AirQCoordinator.device_info` is
updated explicitly, instead of dumping the entire content of (a fully
compatible) `TypedDict`, retrieved from `aioairq`.

* Remove tests ill-suited to this PR

`test_config_flow.test_duplicate_error` slipped through by mistake,
while `test_coordinator.test_fetch_device_info_on_first_update` may need
a more thoroughly suite of accompanying tests

* Ignore airq/coordinator.py

...newly separated from airq/__init__.py, that's already in this list

* Reorder files alphabetically

homeassistant/components/airq/coordinator.py

@@ -0,0 +1,61 @@
+"""The air-Q integration."""
+from __future__ import annotations
+
+from datetime import timedelta
+import logging
+
+from aioairq import AirQ
+
+from homeassistant.config_entries import ConfigEntry
+from homeassistant.const import CONF_IP_ADDRESS, CONF_PASSWORD
+from homeassistant.core import HomeAssistant
+from homeassistant.helpers.aiohttp_client import async_get_clientsession
+from homeassistant.helpers.entity import DeviceInfo
+from homeassistant.helpers.update_coordinator import DataUpdateCoordinator
+
+from .const import DOMAIN, MANUFACTURER, TARGET_ROUTE, UPDATE_INTERVAL
+
+_LOGGER = logging.getLogger(__name__)
+
+
+class AirQCoordinator(DataUpdateCoordinator):
+    """Coordinator is responsible for querying the device at a specified route."""
+
+    def __init__(
+        self,
+        hass: HomeAssistant,
+        entry: ConfigEntry,
+    ) -> None:
+        """Initialise a custom coordinator."""
+        super().__init__(
+            hass,
+            _LOGGER,
+            name=DOMAIN,
+            update_interval=timedelta(seconds=UPDATE_INTERVAL),
+        )
+        session = async_get_clientsession(hass)
+        self.airq = AirQ(
+            entry.data[CONF_IP_ADDRESS], entry.data[CONF_PASSWORD], session
+        )
+        self.device_id = entry.unique_id
+        assert self.device_id is not None
+        self.device_info = DeviceInfo(
+            manufacturer=MANUFACTURER,
+            identifiers={(DOMAIN, self.device_id)},
+        )
+
+    async def _async_update_data(self) -> dict:
+        """Fetch the data from the device."""
+        if "name" not in self.device_info:
+            info = await self.airq.fetch_device_info()
+            self.device_info.update(
+                DeviceInfo(
+                    name=info["name"],
+                    model=info["model"],
+                    sw_version=info["sw_version"],
+                    hw_version=info["hw_version"],
+                )
+            )
+
+        data = await self.airq.get(TARGET_ROUTE)
+        return self.airq.drop_uncertainties_from_data(data)