Cannot delete life event form if still used

[gchi25]

What's expected

Cannot delete life event form if still used in other life event forms in relevant benefits.

What happened

When deleting life event form "Benefit finder: death of a loved one", the auto JSON file generation fails because that the life event form "Benefit finder: death of a loved one" is used in relevant benefits of life event form "Benefit finder: retirement" and "Benefit finder: disability".

How to replicate

Go to life event form "Benefit finder: death of a loved one" edit page
Click "Delete"
The auto JSON file generation fails