Fix some components of ticcmd being blocked in IntermissionThinker

In order to fix a crash related to input on startup, a check was added that ignores jump, movement and look input in case you're not playing. This broke IntermissionThinker input since those field would no longer update. However, since the bug only concerns itself with the intro, it's now changed to only block input during that part.

Fixes #1330 (closed)