* Fixes to setting StreamingChunk.index properly and refactoring tests for conversion
* Make _convert_chat_completion_chunk_to_streaming_chunk a member of OpenAIChatGenerator so we can overwrite it in integrations that inherit from it
* Fixes
* Modify streaming chunk to accept a list of tool call deltas.
* Fix tests
* Fix mypy and update original reno
* Undo change
* Update conversion to return a single streaming chunk
* update to print streaming chunk
* Fix types
* PR comments