fix modal divider

packages/flutter_widgets/lib/src/stream_chat_theme.dart

@@ -491,7 +491,11 @@ class ColorTheme {
       stops: [0, 1],
     ),
     this.borderTop = const Effect(
-        sigmaX: 0, sigmaY: -1, color: Color(0xff000000), blur: 0.0),
+        sigmaX: 0,
+        sigmaY: -1,
+        color: Color(0xff000000),
+        blur: 0.0,
+        alpha: 0.08),
     this.borderBottom = const Effect(
         sigmaX: 0, sigmaY: 1, color: Color(0xff000000), blur: 0.0, alpha: 0.08),
     this.shadowIconButton = const Effect(

packages/flutter_widgets/lib/src/utils.dart

@@ -35,6 +35,7 @@ Future<bool> showConfirmationDialog(
         topRight: Radius.circular(16.0),
       )),
       builder: (context) {
+        final effect = StreamChatTheme.of(context).colorTheme.borderTop;
         return Column(
           mainAxisSize: MainAxisSize.min,
           children: [
@@ -52,8 +53,8 @@ Future<bool> showConfirmationDialog(
             ),
             SizedBox(height: 36.0),
             Container(
-              color: StreamChatTheme.of(context).colorTheme.greyGainsboro,
-              height: 1.0,
+              color: effect.color.withOpacity(effect.alpha ?? 1),
+              height: 1,
             ),
             Row(
               mainAxisAlignment: MainAxisAlignment.spaceBetween,