fix: not able draw boxes in debug ui on single page pdf

Author: prafull-opensignlabs

apps/OpenSign/src/pages/DebugPdf.js

@@ -74,7 +74,7 @@ const DebugPdf = () => {
 
   const inferPdfType = async (pdf) => {
     try {
-      const firstPage = await pdf.getPage(2);
+      const firstPage = await pdf.getPage(pdf?.numPages > 1 ? 2 : 1);
       const scale = 1;
       const { width, height } = firstPage.getViewport({ scale });
       setPdfDimension({ width: width, height: height });