R1:e944cf8ff48e

Propagate "edit policy" and "view policy" when creating a new template task

Summary:
Fixes T4158. Two possible refinements:

- Maybe we should make all of these things respect `ManiphestCapabilityEditAssign::CAPABILITY`, etc. I think it's reasonable either way, and this is probably more intuitive and useful for most cases.
- Maybe we should check that you can see the policies before copying them. Again, this is sort of reasonable either way.

Test Plan: Created a new task from a template, saw that it…