Disabling Issues in a project does not remove the Incidents section

Summary

It is possible to disable the Issues feature from a projects settings but after doing so it is still possible to access the Operations -> Incidents page. On this page is the Create Incident button, and clicking that results in a 404 error.

Steps to reproduce

1. Create a new Project
2. Head into Settings and remove the Issues feature
3. Visit Operations -> Incidents from the left hand navifation
4. Click on the Create Incident button
5. You will get a 404 page

What is the current bug behavior?

Incidents should be removed if Issues have been disabled