Remove unused using

src/Blob/Controllers/BlobController.cs

@@ -11,7 +11,6 @@ using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.AspNetCore.StaticFiles;
-using Microsoft.EntityFrameworkCore.Metadata.Internal;
 using Microsoft.Extensions.Logging;
 using System;
 using System.Collections.Generic;