Things that aren't interactive shouldn't be orange

Addressing nits from rKE2aa3ccc95374

Test Plan:
Run khan-exercises on port 8765, then go to the following urls and make
sure that the problem types work and don't have orange in them.

http://localhost:8765/exercises/division_0.5.html?debug&problem=0
http://localhost:8765/exercises/multiplication_0.5.html?debug&problem=missing-C

Auditors: eater