calls: fix callview not leaving fullscreen on call termination

Change-Id: I8d1c98ee9f814dc6682177acd28f529e75093e49

callwidget.cpp

@@ -741,7 +741,7 @@ void
 CallWidget::slotVideoViewDestroyed(const std::string& callid)
 {
     auto conversation = Utils::getSelectedConversation();
-    if (callid != conversation.uid) {
+    if (conversation.uid.empty() || callid != conversation.callId) {
         return;
     }
     if (ui->mainActivityWidget->isFullScreen()) {