requests/api/project_spec.rb speed up

**What does this MR do?**
It improves the speed of the `request/api/project_spec.rb` tests by ~3 minutes. It also removes some test duplication, and moves some assertions into the same tests so another API call is not needed.

**Before:** `~3.51 min`
**After:** `~ 50 sec.`
Well, I dont think that needs to be tested here, the thing you want to test is that a project is only created if it has all the required params. The models/project_spec.rb does test the validations of the project itself.

@randx What is your opinion on this?