🎨 Use SizedBox.shrink instead of empty SizedBox for placeholder

lib/widgets/account/account_badge.dart

@@ -45,7 +45,7 @@ class _AccountBadgeWidgetState extends State<AccountBadgeWidget> {
   Widget build(BuildContext context) {
     final spec = badges[widget.item.type];
 
-    if (spec == null) return const SizedBox();
+    if (spec == null) return const SizedBox.shrink();
 
     return Tooltip(
       richMessage: TextSpan(

lib/widgets/account/account_heading.dart

@@ -71,7 +71,7 @@ class AccountHeadingWidget extends StatelessWidget {
                             content: banner,
                             fit: BoxFit.cover,
                           )
-                        : const SizedBox(),
+                        : const SizedBox.shrink(),
                   ),
                 ),
               ).paddingSymmetric(horizontal: 16),