Show loading indicator immediately in init as before (#11850)

Change-Id: Ibe91db13b301aaf0a2b5e6e5fb08f566bf5cadab

client/src/com/vaadin/client/ApplicationConnection.java

@@ -438,7 +438,7 @@ public class ApplicationConnection {
 
         tooltip.setOwner(uIConnector.getWidget());
 
-        getLoadingIndicator().trigger();
+        getLoadingIndicator().show();
 
         scheduleHeartbeat();