fix: fixes CTD when suspending the app during a call

- Termination of an application upon suspension is a function
  of available system resources, and my occur during desktop
  change or minimization of the app while in a call. This patch
  removes the actions of the app suspension event handler such as
  hanging up any remaining calls. With this patch applied, abrupt
  termination of the program during a call, will result in a
  hanging call in the peer's client.

Change-Id: Id8c0e6764eb514a39f2c2ca67404ccdc9a765905
Tuleap: #790

MainPage.xaml.cpp

@@ -267,12 +267,12 @@ void RingClientUWP::MainPage::OnstateChange(Platform::String ^callId, RingClient
 void
 MainPage::Application_Suspending(Object^, Windows::ApplicationModel::SuspendingEventArgs^ e)
 {
-    MSG_("Application_Suspending");
+    /*MSG_("Application_Suspending");
     auto deferral = e->SuspendingOperation->GetDeferral();
     Video::VideoManager::instance->captureManager()->CleanupCameraAsync();
     MSG_("Hang up calls...");
     RingD::instance->deinit();
-    deferral->Complete();
+    deferral->Complete();*/
 }
 
 void