Currently, if a block pattern includes an empty column, it displays a giant inserter button in the editor:

This button also appears in the pattern preview:

It generally makes sense to show this inserter in the editor, but it definitely doesn't make much sense to show it in the pattern preview. It only exists to show you that you can insert a block there, but you're not going to be inserting blocks directly within the pattern preview.

Can we hide this inserter from the block pattern previews?