Update comment

Signed-off-by: joshvanl <me@joshvanl.dev>

Author: JoshVanL

dapr/actor/runtime/config.py

@@ -130,9 +130,13 @@ def __init__(
             actor_scan_interval (datetime.timedelta): The duration which specifies how often to scan
                 for actors to deactivate idle actors. Actors that have been idle longer than
                 actor_idle_timeout will be deactivated.
-            drain_ongoing_call_timeout (datetime.timedelta): The duration which specifies the
-                timeout for the current active actor method to finish before actor deactivation.
-                If there is no current actor method call, this is ignored.
+            drain_ongoing_call_timeout (Optional[datetime.timedelta]): The duration which
+                specifies the timeout for the current active actor method to finish before
+                actor deactivation. If there is no current actor method call, this is
+                ignored. Defaults to None, which omits the field from the configuration
+                sent to daprd so the runtime applies its own default. An explicit value
+                must be shorter than the daprd placement dissemination timeout, otherwise
+                daprd will clamp it.
             drain_rebalanced_actors (bool): If true, Dapr will wait for drain_ongoing_call_timeout
                 to allow a current actor call to complete before trying to deactivate an actor.
             reentrancy (ActorReentrancyConfig): Configure the reentrancy behavior for an actor.