fix: event logging with nested chats

[robraux]

Why are these changes needed?

Runtime error encountered with autogen.runtime_logging.start when using nested chats.

Related issue number

Closes #2573

Checks

• I've included any doc changes needed for https://microsoft.github.io/autogen/. See https://microsoft.github.io/autogen/docs/Contribute#documentation to build and test documentation locally.
• I've added tests (if relevant) corresponding to the changes introduced in this PR.
• I've made sure all auto checks have passed.

[ekzhu]

@sonichi pls add @robraux to collaborator

@robraux once added pls open a new PR from a new branch in the Microsoft repo so we can run the open ai tests

[sonichi]

Invited.