added function to remove search text

lib/service/search_provider.dart

@@ -8,5 +8,10 @@ class SearchProvider extends ChangeNotifier {
     if (!silent) notifyListeners();
   }
 
+  void removeSearchText({bool silent = false}) {
+    _searchText = '';
+    if (!silent) notifyListeners();
+  }
+
   String get searchText => _searchText;
 }