message: Fix case-insensitive format for renderBase64
diff: @@ -1071,7 +1071,7 @@ QString WebPage::renderBase64(const QByteArray& format)
  {
  QByteArray nformat = format.toLower();
  - if (format != "pdf" && !QImageWriter::supportedImageFormats().contains(nformat)) {
  + if (nformat != "pdf" && !QImageWriter::supportedImageFormats().contains(nformat)) {
  // Return an empty string in case an unsupported format was provided
  return "";
  }
  @@ -1081,7 +1081,7 @@ QString WebPage::renderBase64(const QByteArray& format)
  QBuffer buffer(&bytes);
  buffer.open(QIODevice::WriteOnly);
  - if (format == "pdf") {
  + if (nformat == "pdf") {
  QPdfWriter pdfWriter(&buffer);
  if (!renderPdf(pdfWriter)) {
  