fix: Minor design fix

lib/views/chat.dart

@@ -560,15 +560,12 @@ class _ChatState extends State<_Chat> {
       body: Stack(
         children: <Widget>[
           if (Matrix.of(context).wallpaper != null)
-            Opacity(
+            Image.file(
-              opacity: 0.66,
-              child: Image.file(
               Matrix.of(context).wallpaper,
               height: double.infinity,
               width: double.infinity,
               fit: BoxFit.cover,
             ),
-            ),
           Column(
             children: <Widget>[
               ConnectionStatusHeader(),
@@ -812,8 +809,7 @@ class _ChatState extends State<_Chat> {
               room.canSendDefaultMessages && room.membership == Membership.join
                   ? Container(
                       decoration: BoxDecoration(
-                        color:
+                        color: Theme.of(context).backgroundColor,
-                            Theme.of(context).backgroundColor.withOpacity(0.8),
                       ),
                       child: Row(
                         crossAxisAlignment: CrossAxisAlignment.end,