Support for new ks240 fan/light wall switch (#839)

In order to support the ks240 which has children for the fan and light
components, this PR adds those modules at the parent level and hides the
children so it looks like a single device to consumers. It also decides
which modules not to take from the child because the child does not
support them even though it say it does. It does this for now via a
fixed list, e.g. `Time`, `Firmware` etc.

Also adds fixtures from two versions and corresponding tests.

kasa/smart/modules/brightness.py

@@ -57,3 +57,7 @@ class Brightness(SmartModule):
             )
 
         return await self.call("set_device_info", {"brightness": brightness})
+
+    async def _check_supported(self):
+        """Additional check to see if the module is supported by the device."""
+        return "brightness" in self.data

kasa/smart/modules/fanmodule.py

@@ -68,3 +68,7 @@ class FanModule(SmartModule):
     async def set_sleep_mode(self, on: bool):
         """Set sleep mode."""
         return await self.call("set_device_info", {"fan_sleep_mode_on": on})
+
+    async def _check_supported(self):
+        """Is the module available on this device."""
+        return "fan_speed_level" in self.data

kasa/smart/modules/lighttransitionmodule.py

@@ -103,6 +103,8 @@ class LightTransitionModule(SmartModule):
 
         Available only from v2.
         """
+        if "fade_on_time" in self._device.sys_info:
+            return self._device.sys_info["fade_on_time"]
         return self._turn_on["duration"]
 
     @property
@@ -138,6 +140,8 @@ class LightTransitionModule(SmartModule):
 
         Available only from v2.
         """
+        if "fade_off_time" in self._device.sys_info:
+            return self._device.sys_info["fade_off_time"]
         return self._turn_off["duration"]
 
     @property
@@ -166,3 +170,11 @@ class LightTransitionModule(SmartModule):
             "set_on_off_gradually_info",
             {"off_state": {**self._turn_on, "duration": seconds}},
         )
+
+    def query(self) -> dict:
+        """Query to execute during the update cycle."""
+        # Some devices have the required info in the device info.
+        if "gradually_on_mode" in self._device.sys_info:
+            return {}
+        else:
+            return {self.QUERY_GETTER_NAME: None}