Fix the UniquePreferenceTest.

By adding in the About Phone v2 screen, we duplicated some settings.

This isn't actually a problem because when the flag to turn on V2 is on,
V1 goes away, and vice versa.

Change-Id: I9aa327ac532ed2ac240bb2d6cbb327f299438889
Bug: 72459760
Test: adb shell am instrument -w -e class
com.android.settings.core.UniquePreferenceTest
com.android.settings.tests.unit/android.support.test.runner.AndroidJUnitRunner