Android: Don't pause when in multi window mode

When the application is in multi window mode then when pausing it should
not suspend the application as it can still be visible in the
background.

Change-Id: I03a561459b2aa04c808b7d4220cd3e558671dd17
Pick-to: 5.15
Reviewed-by: Assam Boudjelthia <assam.boudjelthia@qt.io>

src/android/jar/src/org/qtproject/qt5/android/QtActivityDelegate.java

@@ -909,7 +909,8 @@ public class QtActivityDelegate
 
     public void onPause()
     {
-        QtNative.setApplicationState(ApplicationInactive);
+        if (Build.VERSION.SDK_INT < 24 || !m_activity.isInMultiWindowMode())
+            QtNative.setApplicationState(ApplicationInactive);
     }
 
     public void onResume()