improvements

lib/modules/medical_gas_inspection/models/medical_gas_form_model.dart

@@ -55,7 +55,7 @@ class MedicalGasFormModel {
       'siteId': site?.id,
       'supplierId': supplier?.id,
       'isSubmitted': isSubmitted,
-      'gasRequestDetailDtos': gasRequestDetail?.map((e) => e.toJson()).toList(),
+      'gasRequestDetailDtos': gasRequestDetail != null ? gasRequestDetail?.map((e) => e.toJson()).toList() : [],
     };
   }
 }