open_ai: Make the deltas optional (#39142)

I am using an Azure OpenAI instance since that is what is provided at
work and with how they have it setup not all responses contain a delta,
which lead to errors and truncated responses. This is related to how
they are filtering potentially offensive requests and responses. I don't
believe this filter was made in-house, instead I believe it is provided
by Microsoft/Azure, so I suspect this fix may help other users.

Release Notes:

- N/A

Co-authored-by: Bennet Bo Fenner <bennetbo@gmx.de>
27a18843d4Techy committed on 11/5/2025, 12:47:14 PM· committed by GitHubparent2bc1d60
2 files changedLine totals unavailable