When deleting an image with the delete or backspace keys, the popup buttons aren't hidden

[azaozz]

As the title. We used to hide the buttons on a timeout in 3.4 so this wasn't noticeable.

Was having some slowdown concerns about adding another listener to keydown but this seems quite fast.

One tiny fix in 22717.2.patch (ed wasn't being passed in). Tested both removal of single images, and galleries.

tested 22717.2 and can confirm the patch works as intended and doesn't have any side effects.

Manually tested the TinyMCE manipulation from the console using: tinyMCE.editors[0].plugins.wordpress._hideButtons();

In 23046:

When deleting an image in the editor with the delete or backspace keys, hide the edit and delete popup buttons.

Props azaozz, lessbloat
fixes #22717