fix: correct GlobalUsing.cs namespaces

Remove invalid namespaces:
- EventFlow.Core.Commands (doesn't exist)
- EventFlow.Core.Models.DTOs (doesn't exist)
- EventFlow.Core.Services.Interfaces (doesn't exist)

Remove duplicates:
- EventFlow.Core.Models
- EventFlow.Application.Services
- EventFlow.Application.Validators

Author: alysonsz

EventFlow-API.Tests/GlobalUsing.cs

@@ -5,17 +5,11 @@
 global using Microsoft.EntityFrameworkCore;
 global using Microsoft.AspNetCore.Mvc;
 
-global using EventFlow.Core.Commands;
-global using EventFlow.Core.Models;
-global using EventFlow.Core.Models.DTOs;
-global using EventFlow.Core.Services.Interfaces;
 global using EventFlow.Core.Models;
 global using EventFlow.Core.Primitives;
 global using EventFlow.Core.Repository;
 global using EventFlow.Core.ValueObjects;
 
-global using EventFlow.Application.Services;
-global using EventFlow.Application.Validators;
 global using EventFlow.Application.Abstractions;
 global using EventFlow.Application.Commands;
 global using EventFlow.Application.DTOs;