fix(magnification): fix WindowMagnificationPromptControllerTest fails on target cf_x86_64_auto

Ref to the bug, since the window magnification is not supported for the auto devices, so we add Assume check to skip the tests if window magnification is not supported.

Besides, in test case tapTurnOnAction_isShown_settingsValueIsFalseAndUnregisterReceiver, we find that the Settings getter should be getIntForUser but but not getInt. Because inside getInt it requires the data with contextResolver.getUserId(), which might not equal to the userId used in WindowMagnificationPromptController. Therefore, we should use getIntForUser with TEST_USER as userId to prevent the not-equal issue.

Bug: 315425459
Flag: NA
Test: atest WindowMagnificationPromptControllerTest
Change-Id: Ic4a5a249fcbe0025c78e72f59783deadcd4d3d0c