Gallery Block: Image Filename wp-image-#.jpg (or .png) Causes Block to Crash

#### Steps to reproduce the issue

1. Go to WordPress.com dashboard - Site - Media
2. Upload images that have a filename that starts with wp-image-x, where x is any number or combination of numbers. For example, wp-image-123.jpg or wp-image-2352345.png
3. Upload some images that have working filenames. dog.jpg, cat.jpg, etc..
4. Create a new page.
5. Add a Gallery Block to the page, and only include images that have the wp-image-# file format.
6. Add a second Gallery Block to the page, and only include images that have the working file format (cat.jpg, dog.png, etc).
7. Add a third Gallery Block to the page, and include a mixture of both file names. (wp-image-123.jpg, cat.jpg, dog.png, wp-image-245.png)

#### What I expected
I would expect all of the gallery blocks to work.

#### What happened instead
Gallery blocks that have all images with the wp-image-# format will break entirely, and require a page refresh to exit the gallery. This causes this console error:


Gallery blocks that have all images with a standard filename format will work. That part is okay.

Gallery blocks that have a mixture of the two will work, but images using the wp-image-# format will not appear when flipping through the gallery.

**Screenshots**
A testing site displaying all of the above is available, here:

https://satestsitesc.wordpress.com/gallery-block-bug-test-https-github-com-automattic-jetpack-issues-13632/

Also of note:

Images that have the wp-image-# filename don't have most of the data- elements. For example, a working image might look like this:

``

While a wp-image-# image will look like this:

``

So the split might be failing because `data-orig-size` isn't there. Possibly the root of the console error (screenshot again for posterity):


On the original report, @kwight noted this:
This looks suspect: https://github.com/Automattic/jetpack/blob/master/modules/carousel/jetpack-carousel.php#L396

This is a repost of https://github.com/Automattic/jetpack/issues/13632 - I'm moving it here to file it in the right place (as of now), and close the stale report.

Reproduce the crash with Gallery Blocks containing filenames such as wp-image-123.jpg, then inspect modules/carousel/jetpack-carousel.php around line 396, which the issue identifies as suspect. Compare the available image data for standard and wp-image-# filenames; done means all-image and mixed galleries render and navigate without crashing or omitting images.

Written by the indexing model from the issue text.