Change alert sound for screen share end

Also fix a problem with the screen share alert playing even when
no screen share was running

close #7911

bigbluebutton-html5/imports/ui/components/actions-bar/desktop-share/component.jsx

@@ -81,7 +81,10 @@ const DesktopShare = ({
           },
         }, 'Default error handler for screenshare');
     }
+    // Don't trigger the screen share end alert if presenter click to cancel on screen share dialog
+    if (error && error.name !== 'NotAllowedError') {
       screenShareEndAlert();
+    }
   };
 
   const screenshareLocked = screenshareDataSavingSetting