Fix changing brightness when effect is active (#1019)

This PR changes the behavior of `brightness` module if an effect is
active.
Currently, changing the brightness disables the effect when the
brightness is changed, this fixes that.
This will also improve the `set_effect` interface to use the current
brightness when an effect is activated.

* light_strip_effect: passing `bAdjusted` with the changed properties
changes the brightness.
* light_effect: the brightness is stored only in the rule, so we modify
it when adjusting the brightness. This is also done during the initial
effect activation.

---------

Co-authored-by: Steven B <51370195+sdb9696@users.noreply.github.com>

kasa/smart/modules/__init__.py

@@ -1,5 +1,6 @@
 """Modules for SMART devices."""
 
+from ..effects import SmartLightEffect
 from .alarm import Alarm
 from .autooff import AutoOff
 from .batterysensor import BatterySensor
@@ -54,4 +55,5 @@ __all__ = [
     "WaterleakSensor",
     "ContactSensor",
     "FrostProtection",
+    "SmartLightEffect",
 ]