Deleting a category in wagtail will cause submission answers to not load

[wes-otf]

Describe the bug

When an application form uses a category block, deleting the selected category in wagtail will cause the application to fail to load answers in the submission detail view

To Reproduce

Steps to reproduce the behavior:

1. Create a new submission with an answer that uses a category answer
2. View submission, notice answers load as expected
3. Delete the used category
4. Submission detail view will no longer load the answers outside of named fields

Expected behavior

Submission detail view handles the deleted category with an

Priority

• Medium (slowing you down)

Screenshots

before deleting category

after deleting category