Summary

Adds a new Troubleshooting section to the Image Generation docs documenting GPT Image and GPT Image Edit SKU requirements.

Changes

• Inserted ## Troubleshooting section between the ## Debugging and ## Platform Delivery sections in website/docs/user-guide/features/image-generation.md
• Documents both GPT Image SKU (required for gpt-image-1.5/gpt-image-2) and GPT Image Edit SKU (required for image editing capabilities)
• Provides steps to verify SKUs on the OpenAI API rate limits page
• Recommends preferring these SKUs before falling back to non-OpenAI backends
• Highlights relevance for PT-BR and non-English marketing assets needing native text rendering

Testing

• File renders correctly with 20 new lines inserted
• Markdown syntax is valid (headings, lists, links, bold formatting)

Closes #38516