examples: use task.cancel() when participant leaves or disconnects

CHANGELOG.md

@@ -15,6 +15,14 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fixed a `PipelineTask` issue that was preventing processors to be cleaned up
   after cancelling the task.
 
+### Other
+
+- Updated all examples to use `task.cancel()` instead of pushing an `EndFrame`
+  when a participant leaves/disconnects. If you push an `EndFrame` this will
+  cause the bot to run through everything that is internally queued (which could
+  take seconds). Instead, if a participant disconnects there is nothing else to
+  be sent and therefore we should stop immediately.
+
 ## [0.0.54] - 2025-01-27
 
 ### Added