Fix WindowManagerServiceTests touch tests

WMS#setInTouchMode no longer read
`com.android.internal.R.bool.config_perDisplayFocusEnabled` from
context. Now it reads from mPerDisplayFocusEnabled, so mocking context
and resources won't work.

Bug: 280671905
Test: atest WmTests:WindowManagerServiceTests
Change-Id: I4aaa9f8ee83d173f27ff72b3f0bc1a689426706a