Set pending intent for physical keyboard connection as immutable.

In InputManagerService, set the pending intent of physical keyboard layout notification to be immutable.

Bug: 153878642
Change-Id: I8fb745f7e31dbe3e18ca8547bf75837ecf5176cd

services/core/java/com/android/server/input/InputManagerService.java

@@ -1069,7 +1069,7 @@ public class InputManagerService extends IInputManager.Stub
                     | Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED
                     | Intent.FLAG_ACTIVITY_CLEAR_TOP);
             final PendingIntent keyboardLayoutIntent = PendingIntent.getActivityAsUser(mContext, 0,
-                    intent, 0, null, UserHandle.CURRENT);
+                    intent, PendingIntent.FLAG_IMMUTABLE, null, UserHandle.CURRENT);
 
             Resources r = mContext.getResources();
             Notification notification =