Fixing the a11y floating menu could overlap the taskbar in a foldable device.

Actions:
1. Replacing the DisplayMetrics with WindowMettrics.
2. Using the window inset of the system bar.
3. Rename the "Screen" words to "Display".

Bug: 194073213
Bug: 194071997
Bug: 189193252
Test: atest AccessibilityFloatingMenuViewTest -c
Change-Id: Ic5d88cf3a51b1a230397735b0dda352278c539c4