feat(create-order): 优化合同签订主题显示逻辑

- 在 ContractInfoSignModule 组件中，增加对 return_commpany 字段的判断
- 如果 return_commpany 存在，则显示该值；否则，继续使用原有的签订主题
- 这个修改提高了合同信息的准确性和可读性

Signed-off-by: tangshizhe <48740614+tangshizhe@users.noreply.github.com>

src/views/create-order/components/order-detail-submodule/ContractInfoSignModule.vue

@@ -28,7 +28,8 @@ export default {
       orderDetail: state => state.order.orderDetail
     }),
     setSigningSubject() {
-      return signUnitOptions.find(item => item.value === this.orderDetail?.orderData?.signing_subject)?.label || '-';
+      const { return_commpany } = this.orderDetail?.orderData || {}
+      return return_commpany ? return_commpany : signUnitOptions.find(item => item.value === this.orderDetail?.orderData?.signing_subject)?.label || '-';
     },
     contractResStatus() {
       return this.contractRes?.contract_status === 1