Recently, we reimplemented the watermarks in React. Unfortunately, we
didn't take into account film strip-only mode.

Additionally, we duplicated watermark-related source code on the Welcome
and Conference pages.

If we:
 - pin a remote and click it, unpin is signalled.
 - pin a remote and the click another remote, the new one is pinned and signalled.
 - pin a remote and then click local. UI pins local, but unpinning remote is not signaled, fix addressed with this commit.
 - pin/unpin local, nothing is signalled.

It was not switching and staying on local video on unpinning, after change the last shown video will be used to switch to it.

Adds a property to hide display name and disable update view in SmallVideo. Localvideo hides displayName and disabled update view while users is editing its name and resumes normal behaviour when editing finishes.