Whiteboard student access checkbox broken

[DasGabelhauser]

when a tutor creates a stream, they do not get access to the student access checkbox. gut feeling, the check of whether a host or student is joining the session is not being done properly since the session integration.

[DasGabelhauser]

additionally: students can still draw, although this drawing is not mirrored.

[dmb537]

Drawing now mirrors both ways, but cannot disable student access to whiteboard. Also student gets duplicate copy of drawing which can mess up a bit when lagging, as they get sent back the packets they sent to the server.