dispose method

Implementation

void dispose() {
  currentPageNumber.close();
  isPlayExpanded.close();
  isBold.close();
  scaleFactor.close();
  baseScaleFactor.close();
  isScaling.close();
  isFontDownloaded.close();
  fontsDownloadedList.close();
  fontsSelected.close();
  fontsReady.close();
  fontsLoadProgress.close();
  displayMode.close();
  quranPageRLFocusNode.dispose();
}