Disables the Gesture nav option if 3P launcher is default

Disables the Gesture navigation radio button if 3P launcher is set as
default for current user. Also shows an info icon on the right side that
opens a dialog explaining why it is disables.

Bug: 129532605
Test: Manual test with 3P launcher
Test: make RunSettingsRoboTests ROBOTEST_FILTER=RadioButtonPreferenceWithExtraWidgetTest
Test: make RunSettingsRoboTests ROBOTEST_FILTER=SystemNavigationGestureSettingsTest
Test: make RunSettingsRoboTests ROBOTEST_FILTER=SystemNavigationPreferenceControllerTest

Change-Id: I90000c74246699fa9391ac042c87d7f0ece03637