add allowfullscreen to crocodoc launches
add allowfullscreen to crocodoc launches

fixes RD-4335

DocViewer supports fullscreen, and we are hijacking crocodoc sessions to
show the DocViewer, so let fullscreen happen here. We don't really need
to scope this to just hijacked sessions, since it shouldn't cause any
badness to allow fullscreen on a crocodoc launch too.

Change-Id: I711196d130536aa3f317e16fbb508ade0b8332c8
Reviewed-on: https://gerrit.instructure.com/119508
Tested-by: Jenkins
Product-Review: Caleb Guanzon <54fa1f30d451e4f3c341a8f3c47c9215fd0be9c6@instructure.com>
QA-Review: Caleb Guanzon <54fa1f30d451e4f3c341a8f3c47c9215fd0be9c6@instructure.com>
Reviewed-by: Aaron Kc Hsu <089edc94045de3d9f5f372fb17706d21afcc259f@instructure.com>
Reviewed-by: Josh Orr <a2b6e8624e42637b1fd540dea491d88242856463@instructure.com>

venturehive/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,venturehive/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,djbender/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,venturehive/canvas-lms,sfu/canvas-lms,venturehive/canvas-lms,sfu/canvas-lms,djbender/canvas-lms