refactored react-examples app and created generic test case component

examples/react/src/app.d.ts

@@ -0,0 +1,7 @@
+import { Edge, Node, ReactFlowProps } from '@xyflow/react';
+
+declare global {
+  interface GenericTestCase {
+    reactFlowProps: Omit<ReactFlowProps, 'nodes' | 'edges'> & { nodes: Node[]; edges: Edge[] };
+  }
+}