chore: remove unused dependencies

[swiing]

commit 8984410 has introduced a number of dependencies used by a temporary script. Quote:

// Temporary script to migrate React component metadata
// from .mdx files to .doc.json files.

commit 997f01c has removed the temporary script, but not the associated dependencies.

Suggest to remove all unused dependencies (e.g. mdast-util-from-markdown, and in fact all mdast-***).

More generally speaking, suggest to review and check for unused dependencies.

[hellojanehere]

Hey @swiing ! Wondering if you'd be interested in creating a PR for this for our review?

[swiing]

Hi @hellojanehere , apologize, I have no time, but I have given above description (including links) that should be sufficient for the team to handle this.