fix(project-demand): 修复专项经费选择框逻辑

- 修改了专项经费选择逻辑，确保在选择专项经费时正确处理 specialFund 和 specialFundId 的值
- 优化了代码结构，提高了可读性和维护性

src/views/project-demand/summary/add.vue

@@ -729,10 +729,10 @@ const handleSubmit = debounce(async (instance) => {
     if (formData.value.singleFile !== undefined) {
       formData.value.singleFile = getFileParam(formData.value.singleFile)
     }
-    if (formData.value.isSpecialFund && !formData.value.specialFund) {
+    if (formData.value.isSpecialFund) {
       formData.value.specialFund = getFundName(formData.value.specialFundId)
     }else{
-      formData.value.specialFundId=0
+      formData.value.specialFundId = 0
       formData.value.specialFund=null
     }
     if (formData.value.masterProjectId) {
@@ -792,10 +792,10 @@ const handleResubmit = debounce((instance) => {
       })
     }
     formData.value.optionalChargeLeadership = optionalChargeLeadershipList.value
-    if (formData.value.isSpecialFund && !formData.value.specialFund) {
+    if (formData.value.isSpecialFund) {
       formData.value.specialFund = getFundName(formData.value.specialFundId)
     }else{
-      formData.value.specialFundId=0
+      formData.value.specialFundId = 0
       formData.value.specialFund=null
     }
     if (formData.value.masterProjectId) {