FIX DEV-42115: Remove modify permission check that would grant...

FIX DEV-42115: Remove modify permission check that would grant navigate/interact or controls "permission"
Review #27

Back when media controls (an unfortunately much-overloaded word) was called media permission (also an overloaded word), we granted "permission" for interact/navigate or controls "display" if the requestor agent had modify permissions. This decision doesn't seem to make sense, because it is a common use case to want to "disable" controls (or perhaps interaction/navigate) even for the user who created the object (i.e. who has modify permissions). This removes that check.

NOTE that this check is also made on the server, but in that case modify permissions *grants* the right to navigate in that case. Although the code is very similar, the viewer version is trying to address a use case story, whereas the other is trying to prevent a griefing vector.