fix: Corrected the function names for Actor activate and deactivate.

Author: anirbanbasu

src/py_a2a_dapr/actor/echo_task.py

@@ -32,10 +32,10 @@ def __init__(self, ctx, actor_id):
         self._cancelled = False
         self._history_key = "echo_history"
 
-    async def on_activate(self) -> None:
+    async def _on_activate(self) -> None:
         logger.debug(f"{self.__class__.__name__} activated")
 
-    async def on_deactivate(self) -> None:
+    async def _on_deactivate(self) -> None:
         logger.debug(f"{self.__class__.__name__} deactivated")
 
     async def echo(self, data: dict | None = None) -> dict | None: