rich-text and json: Add onReady prop to expose the editor reference

[OriginalEXE]

👋🏻 Hello,

Right now there seems to be no way to get a reference to the rich-text and json editors when they are initialized. Markdown editor has an onReady prop which is awesome, would you consider adding those to the rich-text and json editors as well?

Thanks

[github-actions[bot]]

Marking issue as stale since there was no acitivty for 30 days