fix (provider/openai): introduce compatibility mode

[lgrammel]

Summary

Introduces a compatibility mode for OpenAI. OpenAI language models do not send stream_options in compatibility mode. Compatibility mode is enabled by default when using createOpenAI. When using the default instance openai, it is set to strict

Reason

1. OpenAI did not sent token usage when streaming for some users
2. PR feat (provider/openai): set stream_options/include_usage to true when streaming #1578 introduced sending stream_options to get token usage
3. This broke streaming for Groq, Fireworks and possibly other providers
4. This PR introduces a compatibility mode to fix it without breaking changes.