refactor(useImport): 简化文件上传逻辑并移除不必要的等待

移除文件上传时的冗余变量声明，并取消对上传任务的强制等待，改为并行处理

src/hooks/useImport.ts

@@ -1502,8 +1502,7 @@ export default () => {
               if (localData) {
                 const uploadTask = (async () => {
                   try {
-                    let file: File
-                    file = await dataToFile(localData, `video_${Date.now()}.mp4`, 'video/mp4')
+                    const file = await dataToFile(localData, `video_${Date.now()}.mp4`, 'video/mp4')
                     if (file) {
                       const url = await uploadFileToS3(file)
                       element.src = url
@@ -1865,7 +1864,8 @@ export default () => {
       }
 
       // 等待当前幻灯片内所有上传任务完成
-      await Promise.all(uploadTasks)
+      // await Promise.all(uploadTasks)
+      Promise.all(uploadTasks)
 
       exporting.value = false
       onclose?.()