[3FT] Launch a selected app when three finger tap is triggered

When clicking on a radio button, we use its key to restore the AppLaunchData, and set the gesture to launch this app.

Demo in comment.

Bug: 399645334
Flag: com.android.settings.flags.touchpad_settings_design_update
Flag: com.android.settings.flags.three_finger_tap_app_launch
Test: TouchpadThreeFingerTapAppSelectionPreferenceControllerTest
Change-Id: I7c3f2da61b4faca85e600e014782a54716e80995