Amin Bandali authored Dec 21, 2020 and Sébastien Blin committed Dec 22, 2020

The recent 990ffe00 commit did not
make changes needed for avatarmanipulation due to recent LRC change
in video threading.  This fixes the regression, and makes the avatar
preview behave similarly to the 'Settings > Media' video preview, and
reuses an existing renderer when possible (e.g. when in an ongoing
call).

Change-Id: I1dfa386318acd7178c1840b79fa173c85128f901