Remove duplicate screenshot view from xml

When the screenshot layout was split to allow only part of it to
respect display insets, a duplicate copy of the
"global_screenshot_animated_view" was created. This wasn't noticed
initially because it has no real effect (starts "gone" and is never
accessed or changed).

Bug: 158470016
Fix: 158470016
Test: manual (built and ensured that the animations/ui still appear
correct)

Change-Id: I2f65c7f800a8ced1592ed92356bb13a3b56a8e81