Tiled gallery breaks when converted from Classic Editor

#### Steps to reproduce the issue

1. Find an old post with a tiled gallery:
https://www.dropbox.com/s/xn3vddkyl7l9187/tiled0_cr.jpg?dl=0

2. Edit the post and push it to Block Editor. Convert the Classic to blocks. Note that your tiled gallery came in as a regular gallery. Duplicate that gallery. Now you have two WordPress galleries:
https://www.dropbox.com/s/otkzu674tvzpx3y/tiled2_cr.jpg?dl=0

3. Convert the second image gallery to a Tiled Gallery, note that the display reflects that in the editor:
https://www.dropbox.com/s/et12325nvldf3a5/tiled4_cr.jpg?dl=0

4. Preview the post and note that the tiled gallery is missing in its entirety:
https://www.dropbox.com/s/2gpbg1gchy3ffcq/tiled5_cr.jpg?dl=0

If you simply convert one image gallery and update the post you will most likely lose even the image gallery and the included image information.

Quite a while back, I reported this problem and it was taken care of. But, the latest updates messed them up again.

The code view shows the tiled gallery in the classic editor becomes a WordPress gallery, and when it block type is changed to the tiled gallery again has a very long part missing. Here is what the code view shows:
< ! -- wp:jetpack/tiled-gallery {"ids":[12609,12611,12612,12613,12610],"linkTo":"media"} /-->

and that code displays a tiled gallery that "appears" to be correct, but it is not.

A properly inserted tiled-gallery in the block editor yields:
< ! -- wp:jetpack/tiled-gallery {"columnWidths":[[66.8426350205179,33.1573649794821],[50,50]],"ids":[12613,12612,12611,12609,12610]} -->

followed by a long code section of a series of div code blocks.

Reproduce the Classic Editor-to-Block Editor conversion using an old post with a tiled gallery, then compare the converted gallery, the Tiled Gallery block markup, and the preview output. Start with the gallery conversion and rendering entry points; done means converting and previewing the post preserves the tiled gallery and its image information without losing the gallery.

Written by the indexing model from the issue text.