Own camera view is reversed until you toggle front/back cameras

This is with riot-ios v0.8.6.

In a video call, the selfie camera would be used by default.
Its view (of yourself) will be strangely reversed. It's **not** acting like a mirror.

If you change to the back camera and then back to the selfie camera again, you'll notice that your own view (of yourself) has changed and **is** like a mirror now.

Reproduce the issue in a video call on riot-ios v0.8.6, starting with the selfie camera and then toggling to the back camera and back. Trace the iOS video-call camera flow to compare the initial self-view with the toggled self-view. Done means the own camera view is mirrored correctly from the start and remains consistent after switching cameras.

Written by the indexing model from the issue text.