[1266] fix formatting

packages/stream_chat_flutter/example/lib/debug/actions/ban_user.dart

@@ -36,4 +36,4 @@ class DebugBanUser extends StatelessWidget {
       ),
     );
   }
-}
+}

packages/stream_chat_flutter/example/lib/debug/actions/shadow_ban.dart

@@ -36,4 +36,4 @@ class DebugShadowBan extends StatelessWidget {
       ),
     );
   }
-}
+}

packages/stream_chat_flutter/example/lib/debug/actions/unban_user.dart

@@ -36,4 +36,4 @@ class DebugUnbanUser extends StatelessWidget {
       ),
     );
   }
-}
+}