Fix failing test enableWindowMagnificationWithScaleOne_enabled_AnimationAndInvokeCallback

The test fails since the magnifier will exceed the boundary with the
targeted X,Y center. Fixing the failure with always moving the magnifier
to the top left corner, within the boundary.

Bug: 306201035
Flag: N/A
Test: atest SystemUITests:WindowMagnificationAnimationControllerTest
Change-Id: If96eb33d86c50e992f1da480ec78137b3b04c714