Fixes asn not being assigned

lib/features/documents/model/query_parameters/id_query_parameter.dart

@@ -2,24 +2,30 @@ import 'package:equatable/equatable.dart';
 import 'package:flutter/widgets.dart';
 
 abstract class IdQueryParameter extends Equatable {
-  final bool _onlyNotAssigned;
+  final int? _assignmentStatus;
   final int? _id;
 
   const IdQueryParameter.notAssigned()
-      : _onlyNotAssigned = true,
+      : _assignmentStatus = 1,
+        _id = null;
+
+  const IdQueryParameter.anyAssigned()
+      : _assignmentStatus = 0,
         _id = null;
 
   const IdQueryParameter.fromId(int? id)
-      : _onlyNotAssigned = false,
+      : _assignmentStatus = null,
         _id = id;
 
   const IdQueryParameter.unset() : this.fromId(null);
 
-  bool get isUnset => _id == null && _onlyNotAssigned == false;
+  bool get isUnset => _id == null && _assignmentStatus == null;
 
-  bool get isSet => _id != null && _onlyNotAssigned == false;
+  bool get isSet => _id != null && _assignmentStatus == null;
 
-  bool get onlyNotAssigned => _onlyNotAssigned;
+  bool get onlyNotAssigned => _assignmentStatus == 1;
+
+  bool get onlyAssigned => _assignmentStatus == 0;
 
   int? get id => _id;
 
@@ -27,13 +33,15 @@ abstract class IdQueryParameter extends Equatable {
   String get queryParameterKey;
 
   String toQueryParameter() {
-    if (onlyNotAssigned) {
-      return "&${queryParameterKey}__isnull=1";
+    if (onlyNotAssigned || onlyAssigned) {
+      return "&${queryParameterKey}__isnull=$_assignmentStatus";
     }
-
-    return isUnset ? "" : "&${queryParameterKey}__id=$id";
+    if (isSet) {
+      return "${queryParameterKey}__id=$id";
+    }
+    return "";
   }
 
   @override
-  List<Object?> get props => [_onlyNotAssigned, _id];
+  List<Object?> get props => [_assignmentStatus, _id];
 }