🔧 chore(minio): 移除过时的兼容性导出

- 删除 MinIOXHRMultipartUploader 别名，统一使用 TaroMinIOMultipartUploader
- 删除 MinIOXHRUploader 别名，统一使用 TaroMinIOUploader
- 清理不再需要的向后兼容代码

mini/src/utils/minio.ts

@@ -411,10 +411,6 @@ export class TaroMinIOUploader {
   }
 }
 
-// 兼容原类名，提供向后兼容
-export const MinIOXHRMultipartUploader = TaroMinIOMultipartUploader;
-export const MinIOXHRUploader = TaroMinIOUploader;
-
 export async function getUploadPolicy(key: string, fileName: string, fileType?: string, fileSize?: number): Promise<MinioUploadPolicy> {
   const policyResponse = await fileClient["upload-policy"].$post({
     json: {