fix(version): 修复应用包上传文件为空时的处理逻辑

- 添加文件存在性检查避免空值传递
- 调整代码顺序确保正确的执行流程
- 防止因空文件导致的应用包检测异常
- 优化上传表单的数据初始化逻辑

tenant-platform/src/views/update/VersionManagementView.vue

@@ -1928,9 +1928,9 @@ function handleAppPlatformChange() {
 
 async function onAppPackageChange(uploadFile: { raw?: File } | null) {
   const file = uploadFile?.raw ?? null
+  if (!file) return
   appUploadForm.value.file = file
   appUploadForm.value.fileUrl = ''
-  if (!file) return
 
   appPackageInspecting.value = true
   appPackageUploadProgress.value = 0