Adding copyright license to recently added files. Minor text label tweak. (#2450)

Author: jwill

material_3_demo/lib/color_box.dart

@@ -1,3 +1,7 @@
+// Copyright 2024 The Flutter team. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 

material_3_demo/lib/component_screen.dart

@@ -2506,7 +2506,7 @@ class _ComponentDecorationState extends State<ComponentDecoration> {
               mainAxisAlignment: MainAxisAlignment.center,
               children: [
                 Text(widget.label,
-                    style: Theme.of(context).textTheme.titleSmall),
+                    style: Theme.of(context).textTheme.titleMedium),
                 Tooltip(
                   message: widget.tooltipMessage,
                   child: const Padding(

material_3_demo/lib/scheme.dart

@@ -1,3 +1,7 @@
+// Copyright 2024 The Flutter team. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
 import 'package:flutter/material.dart';
 
 import '../color_box.dart';