Media Grid: don't try to display images that don't have `data.sizes` set. Also, don't show the "Edit Image" button.

Props ocean90.
Fixes #29245.

Built from https://develop.svn.wordpress.org/trunk@29528


git-svn-id: http://core.svn.wordpress.org/trunk@29304 1a063a9b-81f0-0310-95a4-ce76da25c4cd