chore: Remove django-app-helper

[mrbazzan]

Description

• Remove django-app-helper
• Update test requirements

Checklist

• I have opened this pull request against master
• I have added or modified the tests when changing logic
• I have followed the conventional commits guidelines to add meaningful information into the changelog
• I have read the contribution guidelines and I have joined #workgroup-pr-review on
  Slack to find a “pr review buddy” who is going to review my pull request.

[mrbazzan]

@fsbraun
Was it okay to merge with the failing coverage error?