Cannot scroll to the bottom of the media modal when media library is opened inside a custom block

Problem/Motivation

I can't see the full height of the media modal, and there's no way to scroll to the bottom. If your browser is too short, then you never see the Insert selected button.

You can pull down the height of the modal and see it, but that's not intuitive.

Here's a screenshot of the button partially hidden.

Steps to reproduce

Reduce the height of your browser
Add a custom block with a media field
Add media that opens in the media library
Note that the Insert selected button is not visible or cut off and that you can't scroll to the bottom.

Proposed resolution

Allow users to scroll to the bottom of the media modal