fix(flutter): 修复首页冷启动灰屏

lib/core/widgets/remote_image.dart

@@ -16,6 +16,7 @@ class RemoteImage extends StatelessWidget {
     this.showFallbackIcon = false,
     this.fallbackIconKey,
     this.fallbackAspectRatio,
+    this.fallbackColor = AppColors.bar,
   });
 
   final String path;
@@ -25,6 +26,7 @@ class RemoteImage extends StatelessWidget {
   final bool showFallbackIcon;
   final Key? fallbackIconKey;
   final double? fallbackAspectRatio;
+  final Color fallbackColor;
 
   @override
   Widget build(BuildContext context) {
@@ -47,7 +49,7 @@ class RemoteImage extends StatelessWidget {
     final fallback = Container(
       width: width,
       height: height,
-      color: AppColors.bar,
+      color: fallbackColor,
       alignment: Alignment.center,
       child: showFallbackIcon
           ? Icon(