fixing analysis issues

Author: pavanpodila

packages/demo/lib/example_browser.dart

@@ -26,7 +26,6 @@ class ExampleBrowser extends StatefulWidget {
 class _ExampleBrowserState extends State<ExampleBrowser> {
   late final ExampleNavigationState _navState;
   Example? _selectedExample;
-  String? _selectedCategoryId;
   final GlobalKey<ScaffoldState> _scaffoldKey = GlobalKey<ScaffoldState>();
 
   @override
@@ -50,7 +49,6 @@ class _ExampleBrowserState extends State<ExampleBrowser> {
     if (example != null) {
       setState(() {
         _selectedExample = example;
-        _selectedCategoryId = categoryId;
       });
       _navState.selectExample(exampleId);
     }

packages/demo/lib/examples/basics/controlling_nodes.dart

@@ -64,10 +64,14 @@ class _ControllingNodesExampleState extends State<ControllingNodesExample> {
     _controller.addNode(node);
   }
 
-  Node<Map<String, dynamic>> _createNode(String nodeType, int counter,
-      [Offset? position]) {
+  Node<Map<String, dynamic>> _createNode(
+    String nodeType,
+    int counter, [
+    Offset? position,
+  ]) {
     // Use provided position or generate random position
-    final nodePosition = position ??
+    final nodePosition =
+        position ??
         Offset(
           100.0 + math.Random().nextDouble() * 400,
           100.0 + math.Random().nextDouble() * 300,
@@ -291,7 +295,6 @@ class _ControllingNodesExampleState extends State<ControllingNodesExample> {
     final innerRadius = math.max(0.0, outerRadius - borderWidth);
 
     final theme = Theme.of(context);
-    final isDark = theme.brightness == Brightness.dark;
     final colorType =
         node.data['colorType'] as String? ?? 'surfaceContainerHighest';