R1:e6925c83c187

Do not hardcode default Priority names in Project Reports tooltip

Summary:
Pull the names of Priority field values instead of hardcoding them.

Closes T15799

Test Plan:
* As an admin, go to `/config/edit/maniphest.priorities/` and change the value of `"name"` of a Priority value with a value < `50` (e.g.: Low, Wishlist)
* Open `/maniphest/report/project/`
* Hover over the `Oldest (Pri)` column and check the tooltip text before and after applying this patch

Reviewers: O1 Blessed Committers, valerio.