Resent the data event if there is no code found

In case we move it out of view and back again we want a second event. The user can filter those
out if needed.

packages/qr-code-scanner/src/qr-code-scanner.js

@@ -315,6 +315,7 @@ export class QrCodeScanner extends ScopedElementsMixin(DBPLitElement) {
                 } else {
                     outputMessage.hidden = false;
                     outputData.parentElement.hidden = true;
+                    lastSentData = null;
                 }
             }
             if (video.readyState === video.HAVE_ENOUGH_DATA && !scroll) {