Remove unnecessary using directive in DwSql query builder unit test

Author: souvikghosh04

src/Service.Tests/UnitTests/DwSqlQueryBuilderUnitTests.cs

@@ -7,7 +7,6 @@
 using Azure.DataApiBuilder.Config.DatabasePrimitives;
 using Azure.DataApiBuilder.Config.ObjectModel;
 using Azure.DataApiBuilder.Core.Authorization;
-using Azure.DataApiBuilder.Core.Models;
 using Azure.DataApiBuilder.Core.Resolvers;
 using Azure.DataApiBuilder.Core.Services;
 using Microsoft.AspNetCore.Http;