Added download option for assignment cards

Export PDF Download to hook
Prevented some NaN's

src/utils/pdf.ts

@@ -22,22 +22,23 @@ export const getRadialProgressPNG = (
   // calculate the percentage of the score
   // and round it to the closest available image
   const percent = (score / total) * 100;
+  if (isNaN(percent)) return `public/radial_progress/${color}_0.png`;
   const remainder = percent % 10;
   const roundedPercent = percent - remainder;
   return `public/radial_progress/${color}_${roundedPercent}.png`;
 };
 
 export const streamToBuffer = async (
-    stream: NodeJS.ReadableStream
-  ): Promise<Buffer> => {
-    return new Promise((resolve, reject) => {
-      const chunks: Buffer[] = [];
-      stream.on("data", (data) => {
-        chunks.push(data);
-      });
-      stream.on("end", () => {
-        resolve(Buffer.concat(chunks));
-      });
-      stream.on("error", reject);
+  stream: NodeJS.ReadableStream
+): Promise<Buffer> => {
+  return new Promise((resolve, reject) => {
+    const chunks: Buffer[] = [];
+    stream.on("data", (data) => {
+      chunks.push(data);
     });
-  };
+    stream.on("end", () => {
+      resolve(Buffer.concat(chunks));
+    });
+    stream.on("error", reject);
+  });
+};