fix(SingleUpload.vue): 修复handleRemove的TypeScript编译报错问题

src/components/Upload/SingleUpload.vue

@@ -89,10 +89,12 @@ function handleExceed(files: UploadFile[]) {
  *
  * @param file
  */
-function handleRemove(file: string) {
+function handleRemove(file: string | null) {
+  if (file) {
     deleteFile(file)
     imgUrl.value = null // 这里会触发imgUrl的computed的set方法
   }
+}
 
 function handleBeforeUpload(file: any) {
   const isJPG = file.type === 'image/jpeg'
@@ -120,16 +122,19 @@ function handleBeforeUpload(file: any) {
     &:hover {
       border-color: #409EFF;
     }
+
     &-icon {
       font-size: 28px;
       color: #8c939d;
       text-align: center;
     }
+
     &-image {
       width: 146px;
       height: 146px;
       display: block;
     }
+
     &-remove-icon {
       font-size: 12px;
       color: #ff4d51 !important;