docs: update IBM watsonx.ai docs (#17932)
- **Description:** Update IBM watsonx.ai docs and add IBM as a provider
docs
- **Dependencies:**
[ibm-watsonx-ai](https://pypi.org/project/ibm-watsonx-ai/),
- **Tag maintainer:** :
Please make sure your PR is passing linting and testing before
submitting. Run `make format`, `make lint` and `make test` to check this
locally. ✅
