rename colors

packages/stream_chat_flutter/example/lib/tutorial-part-3.dart

@@ -101,12 +101,12 @@ class ChannelListPage extends StatelessWidget {
             StreamChatTheme.of(context).channelPreviewTheme.title!.copyWith(
                   color: StreamChatTheme.of(context)
                       .colorTheme
-                      .black
+                      .textHighEmphasis
                       .withOpacity(opacity),
                 ),
       ),
       subtitle: Text(subtitle),
-      trailing: channel.state!.unreadCount! > 0
+      trailing: channel.state!.unreadCount > 0
           ? CircleAvatar(
               radius: 10,
               child: Text(channel.state!.unreadCount.toString()),

packages/stream_chat_flutter/example/lib/tutorial-part-6.dart

@@ -50,9 +50,9 @@ class MyApp extends StatelessWidget {
         ),
       ),
       otherMessageTheme: MessageTheme(
-        messageBackgroundColor: colorTheme.black,
+        messageBackgroundColor: colorTheme.textHighEmphasis,
         messageText: TextStyle(
-          color: colorTheme.white,
+          color: colorTheme.barsBg,
         ),
         avatarTheme: AvatarTheme(
           borderRadius: BorderRadius.circular(8),