Fix the issue of fullscreen and window Magnification using different multi-tap delay times

Consistently utilize the existing magnification API to retrieve the specific delay time.

Bug: 356295479
Test: manual
atest -c WindowMagnificationGestureHandlerTest
atest -c FullScreenMagnificationGestureHandlerTest
Flag: EXEMPT bugfix
Change-Id: Ic8e52d3c4d49d5a1cc5cd981c3e53a2c04b5e707