Fix editor overflow

[pandah3]

Changes proposed in this Pull Request

*Fixes editor overflow so that when media is added while user is creating a post, the page stays where the user inserted the media so they don't have to scroll back down to where they were.

Testing instructions

Starting at URL: https://wordpress.com/post

• Add content to a new post. Make sure it's enough content so the first line scrolls off the top of the screen.

• Click "add" button, click "media", select an image, and click "insert".

• After image (or hyperlink) is inserted, page jumps back to the top of the page, rather than staying at the inserted media location.

• Bug fixed; page stays at current user location after inserting media

• Fixes Adding media using the "add" button on the toolbar causes the editor to jump to the top of the page #27806 , Editor: Adding a link using toolbar button causes editor to jump to the top #27226

[pandah3]

cc @jameskoster Fixed this issue here: https://github.com/Automattic/wp- calypso/issues/16873#issuecomment-321504661

However, the proposed fix directly breaks PR #26577, which added the deleted block of code to prevent background scrolling when the modal is clicked.

I created a new PR that address both these issues here: PR #28737

[github-actions]

This PR has been marked as stale due to lack of activity within the last 30 days.

[sixhours]

Hi there! 👋 Looks like this was handled in #29832 so I'm going to close this out. But thanks very much for your contribution!