[wip] 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.
Prefer single-quoted strings when you don't need string interpolation or special symbols.