fix: handle sessionStorage retrieval and setGraphData in GraphVisualization component

Signed-off-by: Yash Bhesaniya <yashbhesaniya1999@gmail.com>

Author: yashbhesaniya

Project/frontend/src/components/Graph/index_visjs.tsx

@@ -229,12 +229,17 @@ const GraphVisualization: React.FC = () => {
 
   useEffect(() => {
     const fetchGraphData = async () => {
+      if (sessionStorage.getItem(fileId)) {
+        setGraphData(JSON.parse(sessionStorage.getItem(fileId) as string));
+        setIsLoading(false);
+        return;
       try {
         const response = await fetch(
           `${import.meta.env.VITE_BACKEND_HOST}${VISUALIZE_API_PATH.replace(':fileId', fileId)}`,
         );
         const data = await response.json();
         setGraphData(data);
+        sessionStorage.setItem(fileId, JSON.stringify(data));
 
         // Get the list of unique topics
         const uniqueTopics = Array.from(