Remove unused namespace imports from Program.cs

Cleaned up Program.cs by removing unnecessary using directives
for AutoMapper, DbFirst, and EntityFrameworkCore namespaces.
This reduces clutter and improves code maintainability.

DbFirst.API/Program.cs

@@ -1,4 +1,3 @@
-using AutoMapper;
 using DbFirst.Application.Catalogs;
 using DbFirst.Domain.Repositories;
 using DbFirst.Infrastructure;