azure-openai needs docstring updates for sphinx version 8.2.0

**ACTION NEEDED:** This version of sphinx will be merged on **2026-10-12**. The build will begin to fail for this library if errors are not fixed.

**Library name:** azure-openai
**Sphinx version:** 8.2.0
**Sphinx Build:** [Link to build (2026-07-25)](https://dev.azure.com/azure-sdk/internal/_build/results?buildId=6616841&view=logs&j=87f850b5-cf15-53c6-370a-4be21ee70ec7&t=82919efa-82d6-5dc4-2e9a-f82117bff292)
**How to fix:** Run the `next-sphinx` azpysdk command at the library package-level and resolve the docstring errors.
1) `/mnt/vss/_work/1/s>pip install -e ./eng/tools/azure-sdk-tools`
2) `../azure-openai>azpysdk next-sphinx --isolate .`

See the [Sphinx and docstring checker](https://github.com/Azure/azure-sdk-for-python/blob/main/doc/eng_sys_checks.md#sphinx-and-docstring-checker) for more information.