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/effects.py

@@ -2,8 +2,33 @@
 
 from __future__ import annotations
 
+from abc import ABC, abstractmethod
 from typing import cast
 
+from ..interfaces.lighteffect import LightEffect as LightEffectInterface
+
+
+class SmartLightEffect(LightEffectInterface, ABC):
+    """Abstract interface for smart light effects.
+
+    This interface extends lighteffect interface to add brightness controls.
+    """
+
+    @abstractmethod
+    async def set_brightness(self, brightness: int, *, transition: int | None = None):
+        """Set effect brightness."""
+
+    @property
+    @abstractmethod
+    def brightness(self) -> int:
+        """Return effect brightness."""
+
+    @property
+    @abstractmethod
+    def is_active(self) -> bool:
+        """Return True if effect is active."""
+
+
 EFFECT_AURORA = {
     "custom": 0,
     "id": "TapoStrip_1MClvV18i15Jq3bvJVf0eP",