Jetpack AI: Get "Make Post From List" functionality working

[mwatson]

Similar to re-enabling the "Transform list into table" functionality (and all changes required), we can likewise re-implement the "create post from list" feature for Jetpack AI. This will require similar but different code changes.

[github-actions]

OpenAI suggested the following labels for this issue:

• [Feature Group] Content Management: The issue pertains to the management and creation of content features within the Jetpack AI plugin.
• [Feature] Publicize: The 'make post from list' functionality is related to automatically sharing posts, similar to the publicizing aspects of Jetpack.
• [Feature] Shortcodes / Embeds: This feature could involve embedding lists or transforming content into structured formats that enhance user interaction.
• [Feature] WordPress.com Block Editor: As the feature relates to creating posts, it is connected to the block editor experience used for managing content.