Fix Wi-Fi Easy Connect QR code scanner problems

1. When camera area overlaps display cutout, it's onLayout size is 0/0.
   To fix it, use ConstraintLayout to specify width and height in layout file.

2. When scanned a QR code and there is an error, set camera area frame line
   back to unfocused color.

Bug: 124399763
Test: manual test
Change-Id: I7575efd0ccfb58d114acc3dcca6978d68b801f91