Fixed bugs, added serialization for documents state

lib/core/interceptor/dio_http_error_interceptor.dart

@@ -47,7 +47,7 @@ class DioHttpErrorInterceptor extends Interceptor {
         errorMessages.putIfAbsent(entry.key, () => entry.value.toString());
       }
     }
-    return handler.reject(
+    handler.reject(
       DioError(
         error: errorMessages,
         requestOptions: err.requestOptions,

lib/core/type/types.dart

@@ -1,2 +1,8 @@
 typedef JSON = Map<String, dynamic>;
 typedef PaperlessValidationErrors = Map<String, String>;
+typedef PaperlessLocalizedErrorMessage = String;
+
+extension ValidationErrorsUtils on PaperlessValidationErrors {
+  bool get hasFieldUnspecificError => containsKey("non_field_errors");
+  String? get fieldUnspecificError => this['non_field_errors'];
+}