Clean up flag(1): com.android.window.flags.always_draw_magnification_fullscreen_border

Clean up the flag usages in the services/accessibility directory.

Bug: 377211252
Test: atest FullScreenMagnificationControllerTest
Test: atest MagnificationControllerTest
Test: atest AccessibilityManagerServiceTest
Flag: com.android.window.flags.always_draw_magnification_fullscreen_border
Change-Id: I78aeb95c7b21170f1536c9d3f85e96e993ee2ef4
6 files changed