Steps to reproduce

1. Starting at URL: https://wordpress.com/block-editor/post
2. Create a new post using the block editor and add a classic block
3. Click the Add Media button in the block toolbar
4. Attempt to select multiple images to create a gallery

What I expected

To be able to select multiple images, as in the classic Calypso editor, that will then change the action button to the Create Gallery option rather than immediately inserting the image

What happened instead

Selecting a second image causes the first image to be deselected, in other words, there's no way to select multiple images at once.

Wonder if it might be related to the change to the classic block media modal in #31596. @mmtr?

Context / Source

Discovered while trying to replicate an unrelated issue.