Update selection_dialog.dart

lib/selection_dialog.dart

@@ -13,6 +13,7 @@ class SelectionDialog extends StatefulWidget {
   final double flagWidth;
   final Size size;
   final bool hideSearch;
+  final Icon closeIcon;
 
   /// elements passed as favorite
   final List<CountryCode> favoriteElements;
@@ -30,9 +31,11 @@ class SelectionDialog extends StatefulWidget {
     this.flagWidth = 32,
     this.size,
     this.hideSearch = false,
+    this.closeIcon = closeIcon == null ? Icon(Icons.close) : closeIcon,
   })  : assert(searchDecoration != null, 'searchDecoration must not be null!'),
-        this.searchDecoration =
-            searchDecoration.copyWith(prefixIcon: Icon(Icons.search)),
+        this.searchDecoration = searchDecoration.prefixIcon == null
+            ? searchDecoration.copyWith(prefixIcon: Icon(Icons.search))
+            : searchDecoration,
         super(key: key);
 
   @override
@@ -72,9 +75,7 @@ class _SelectionDialogState extends State<SelectionDialog> {
                   IconButton(
                     padding: const EdgeInsets.all(0),
                     iconSize: 20,
-                    icon: Icon(
-                      Icons.close,
-                    ),
+                    icon: closeIcon,
                     onPressed: () => Navigator.pop(context),
                   ),
                   if (!widget.hideSearch)