fix: theme channel_list_view.dart background color in the proper place

packages/stream_chat_flutter/lib/src/channel_list_view.dart

@@ -231,9 +231,12 @@ class _ChannelListViewState extends State<ChannelListView> {
       );
     }
 
-    return LazyLoadScrollView(
+    return ColoredBox(
+      color: ChannelListViewTheme.of(context).backgroundColor!,
+      child: LazyLoadScrollView(
         onEndOfPage: () => _channelListController.paginateData!(),
         child: child,
+      ),
     );
   }
 
@@ -571,10 +574,6 @@ class _ChannelListViewState extends State<ChannelListView> {
                         },
                 ),
             ],
-        child: DecoratedBox(
-          decoration: BoxDecoration(
-            color: chatThemeData.channelListViewTheme.backgroundColor,
-          ),
         child: widget.channelPreviewBuilder?.call(context, channel) ??
             ChannelPreview(
               onLongPress: widget.onChannelLongPress,
@@ -583,7 +582,6 @@ class _ChannelListViewState extends State<ChannelListView> {
               onTap: (channel) => onTap(channel, widget.channelWidget),
             ),
       ),
-      ),
     );
   }