see #12874: provide the exception to the StreamChatErrorEvent

[ziodave]

Description

The StreamChatErrorEvent now provides the exception that caused the error.

Fixes #12874

New Package?

• Yes
• No

Version Bump?

• Yes
• No

Type of Change

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

• Added new unit/integration tests
• Added new notebook (that tests end-to-end)
• I stared at the code and made sure it makes sense

Suggested Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added Google Colab support for the newly added notebooks.
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I ran make format; make lint to appease the lint gods

[logan-markewich]

Thanks @ziodave !