AI Assistant: Parse Gutenberg syntax and not only markdown

[nunyvega]

Initially we won't use streaming mode.

Related initial changes: AI Assistant Gutenberg experiment

[retrofox]

Let us handle this situation in the most effective manner. It would be best to progressively display the content upon receiving the endpoint response. However, if this is not feasible, we could incorporate an animation or similar feature to notify users that the content is being generated.

[github-actions[bot]]

This issue has been marked as stale. This happened because:

• It has been inactive for the past 6 months.
• It hasn’t been labeled `[Pri] BLOCKER`, `[Pri] High`, `[Type] Feature Request`, `[Type] Enhancement`, `[Type] Janitorial`, `Good For Community`, `[Type] Good First Bug`, etc.

No further action is needed. But it's worth checking if this ticket has clear reproduction steps and it is still reproducible. Feel free to close this issue if you think it's not valid anymore — if you do, please add a brief explanation.