Make get_module return typed module (#892)

Passing in a string still works and returns either `IotModule` or
`SmartModule` type when called on `IotDevice` or `SmartDevice`
respectively. When calling on `Device` will return `Module` type.

Passing in a module type is then typed to that module, i.e.:
```py
smartdev.get_module(FanModule)  # type is FanModule
smartdev.get_module("FanModule")  # type is SmartModule
```
Only thing this doesn't do is check that you can't pass an `IotModule`
to a `SmartDevice.get_module()`. However there is a runtime check which
will return null if the passed `ModuleType` is not a subclass of
`SmartModule`.

Many thanks to @cdce8p for helping with this.

kasa/tests/smart/features/test_brightness.py

@@ -33,7 +33,7 @@ async def test_brightness_component(dev: SmartDevice):
 
 
 @dimmable
-async def test_brightness_dimmable(dev: SmartDevice):
+async def test_brightness_dimmable(dev: IotDevice):
     """Test brightness feature."""
     assert isinstance(dev, IotDevice)
     assert "brightness" in dev.sys_info or bool(dev.sys_info["is_dimmable"])

kasa/tests/smart/modules/test_fan.py

@@ -1,5 +1,3 @@
-from typing import cast
-
 import pytest
 from pytest_mock import MockerFixture
 
@@ -13,7 +11,7 @@ fan = parametrize("has fan", component_filter="fan_control", protocol_filter={"S
 @fan
 async def test_fan_speed(dev: SmartDevice, mocker: MockerFixture):
     """Test fan speed feature."""
-    fan = cast(FanModule, dev.get_module("FanModule"))
+    fan = dev.get_module(FanModule)
     assert fan
 
     level_feature = fan._module_features["fan_speed_level"]
@@ -38,7 +36,7 @@ async def test_fan_speed(dev: SmartDevice, mocker: MockerFixture):
 @fan
 async def test_sleep_mode(dev: SmartDevice, mocker: MockerFixture):
     """Test sleep mode feature."""
-    fan = cast(FanModule, dev.get_module("FanModule"))
+    fan = dev.get_module(FanModule)
     assert fan
     sleep_feature = fan._module_features["fan_sleep_mode"]
     assert isinstance(sleep_feature.value, bool)
@@ -57,7 +55,8 @@ async def test_sleep_mode(dev: SmartDevice, mocker: MockerFixture):
 async def test_fan_interface(dev: SmartDevice, mocker: MockerFixture):
     """Test fan speed on device interface."""
     assert isinstance(dev, SmartDevice)
-    fan = cast(FanModule, dev.get_module("FanModule"))
+    fan = dev.get_module(FanModule)
+    assert fan
     device = fan._device
     assert device.is_fan