Adjusts the draggable bounds with the display cutcout

Some models support different display cutout by default.
To make the magnification switch button not to overlap the display
cutout and systemBars, we have to adjust the draggable bounds with
the display cutout window insets.

Bug: 189054814
Test: atest MagnificationModeSwitchTest,
Manual test,
Enable magnification settings and show the switch button.
Go to System settings > Developer options > Display cutout
Chaneg the cutout settings to monitor if the UI is expected

Change-Id: Iaa0ae0ad828e8460ff1e62b1b6e4616245b86b58