Back to old-style locations for course staff info

The LMS team has updated the instructor dash to use old-style locations, so we should go back to displaying old-style locations in the course staff debug info.

Revert "Show new-style locations in course staff debug info (opaque keys update)"
This reverts commit 24df7773beffa932b04a66345a764a0f2ac34c2c.

@dianakhuang