Numeric block attributes reset to default values #3761

Describe the bug
Opening an older post in the editor causes some block settings to be reset to their default values. The frontend initially appears correct because the previously saved CSS is still intact. However, once the post is saved in the editor, the default value is applied back to the block.

To Reproduce
Steps to reproduce the behavior:

1. Add this code
   <!-- wp:stackable/hero {"uniqueId":"abc1234","containerHeight":50} /-->
2. Save the post
3. See error in editor (Container Min. Height is 500)

Expected behavior
The block should preserve the applied containerHeight value in the editor.

Screenshots