Backup settings for Assistant invocation

This backs up two more settings:
 * "Use long press home for Assistant" (if user uses 3-button
   navigation)
 * "Use corner-swipe for Assistant" (if user uses gesture navigation)

Since we changed the defaults for these settings between OS generations,
users have been losing their interaction settings when migrating.

Bug: 242160733
Test: atest SettingsBackupTest
      (Temporarily reenabled secureSettingsBackedUpOrDenied)
Change-Id: If4a0fd112f68aebbc343efc9e0d6ccbbe6b89036
Merged-In: If4a0fd112f68aebbc343efc9e0d6ccbbe6b89036

packages/SettingsProvider/src/android/provider/settings/backup/SecureSettings.java

@@ -210,6 +210,8 @@ public class SecureSettings {
         Settings.Secure.LOCKSCREEN_SHOW_WALLET,
         Settings.Secure.LOCK_SCREEN_SHOW_QR_CODE_SCANNER,
         Settings.Secure.LOCKSCREEN_USE_DOUBLE_LINE_CLOCK,
-        Settings.Secure.STATUS_BAR_SHOW_VIBRATE_ICON
+        Settings.Secure.STATUS_BAR_SHOW_VIBRATE_ICON,
+        Settings.Secure.ASSIST_TOUCH_GESTURE_ENABLED,
+        Settings.Secure.ASSIST_LONG_PRESS_HOME_ENABLED
     };
 }