Reduce Bundle Size by lazy loading markdown-it

What does this MR do?

This reduces the bundle size of main.js by lazy loading the markdown libraries only in the case that something was copied (as this is the only dependency) from 17.85 MB Parsed (before echarts update) to 14.75 MB.

Before (markdown-it + prosemirror libraries)

After:

• In copy_as_gfm.js is now the nodeToGFM async and loads the bundles first async.
• Specs needed to be adapted to work with the async loading.

What are the relevant issue numbers?

Closes #56989 (closed)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated via this MR
• Documentation reviewed by technical writer or follow-up review issue created
• Tests added for this feature/bug
• Tested in all supported browsers
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides
• Link to e2e tests MR added if this MR has Requires e2e tests label. See the Test Planning Process.
• Security reports checked/validated by reviewer