show call controls when waiting for connection

[mahibi]

Steps to reproduce

1. start videocall
2. don't join with other participants

Expected behaviour

• call controls remain visible until connection is established (add logic to suppress disappearing in animation method)
• or at least they must appear when tapping on the screen (--> add onTouchListener for gridView wrapper)

Actual behaviour

call controls hide after some seconds. no possibility to hang up

[mahibi]

this is especially confusing when - for whatever reason - the connection fails to be established..