Disable fill dialog on Automotive with multi-window

The autofill fill dialog should be disabled on Automotive multi-window
until it is fixed.

Bug: 420943436
Fix: 419125012
Test: atest CtsAutoFillServiceTestCases:LoginActivityTest#testCancelFillDialog_showDropdown_v2
Flag: android.service.autofill.disable_fill_dialog_on_automotive_multi_window
Change-Id: I52e98b57042b7dba6a96f76ad847465f06a4e3ef