Add EventActions to ADK->A2A conversion

Event.py currently omits [Event.actions](https://github.com/google/adk-python/blob/a3aa07722a7de3e08807e86fd10f28938f0b267d/src/google/adk/events/event.py#L51) during ADK -> A2A event conversion, which is problematic for consumers of the A2A events that need data like state_delta, artifact_delta, etc.
