fix: Opening file whose type is Knowledge Graph appear error with tsx #1975 (#1978)

### What problem does this PR solve?

fix: Opening file whose type is Knowledge Graph appear error with tsx
#1975
### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

web/src/components/indented-tree/indented-tree.tsx

@@ -369,9 +369,9 @@ const IndentedTree = ({ data, show }: IProps) => {
 
     graphRef.current = graph;
 
-    graph.setData(treeToGraphData(data));
+    graph?.setData(treeToGraphData(data));
 
-    graph.render();
+    graph?.render();
   }, []);
 
   useEffect(() => {