Draft: Resolve "Feedback on deleted request breaks assistant statistics page"

What does this mr do?

See #707 (closed) for desc of bug.

Actions taken to fix bug

Does this MR meet the acceptance criteria?

• I have added a changelog entry to reflect the significant changes I made and the bug I fixed.
• A test was created to test the bug.
• I have updated the documentation accordingly.
• I adhere to the style guide.

Closes #707 (closed)