Only show "currently playing" pop over on pages that do not have their own stream

[mariobehling]

When an attendee views a stream and then switches to another stream the first stream will move to the top right as a pop over and continue playing.

Expected: Only show "currently playing" pop over on pages that do not have their own stream, e.g. schedule or sessions page. Do not add a pop-over if the user moves to another stream.