ui: fixes in update checker ui

* init updatecheck ui with "checking for update..." to counter the effect of the timer start delay
* removed message box telling the user "everything is ok" after manual (forced) update check

src/lib_gui/qt/element/QtUpdateCheckerWidget.cpp

@@ -28,6 +28,8 @@ QtUpdateCheckerWidget::QtUpdateCheckerWidget(QWidget* parent)
 	{
 		if (QtUpdateChecker::needsAutomaticCheck())
 		{
+			m_button->setText("checking for update...");
+			m_button->setEnabled(false);
 			QTimer::singleShot(250,
 				[this]()
 				{

src/lib_gui/qt/network/QtUpdateChecker.cpp

@@ -156,16 +156,6 @@ void QtUpdateChecker::check(bool force, std::function<void(Result)> callback)
 						QDesktopServices::openUrl(QUrl(url, QUrl::TolerantMode));
 					}
 				}
-				else if (force)
-				{
-					QMessageBox msgBox;
-					msgBox.setText("Update Check");
-					msgBox.setInformativeText(
-						("Sourcetrial " + Version::getApplicationVersion().toDisplayString() + " is still up-to-date.").c_str());
-					msgBox.setStandardButtons(QMessageBox::Ok);
-					msgBox.setDefaultButton(QMessageBox::Ok);
-					msgBox.exec();
-				}
 			}
 			while (false);