Post recording improvements

 - Rework how the video player works. This fixes backing from another activity at a cost of it being reinitialized every time;
 - Fix snackbar clickabke area;
 - Show "Video saved" once;

Flag: com.android.systemui.new_screen_record_toolbar
Fixes: 430553811
Test: manual on foldable
Change-Id: I33da6775f8720df10a6dd12d64ca1d8ac90664db