Refactor: Remove IOutgoingEmailConsumer interface

Simplified the codebase by removing the `IOutgoingEmailConsumer` interface and directly using the `OutgoingEmailConsumer` class.

- Removed `IOutgoingEmailConsumer` from the application.
- Updated `DependencyInjection` to register `OutgoingEmailConsumer` directly.
- Modified `OutgoingEmailConsumer` to no longer implement the removed interface.
- Updated `AsyncInitWorker` to depend directly on `OutgoingEmailConsumer`.
- Simplified initialization logic for email consumer and publisher.

These changes eliminate an unnecessary abstraction layer, making the code easier to maintain while preserving functionality.

src/DigitalData.MessagingService.Infrastructure/Queue/OutgoingEmailConsumer.cs

@@ -15,7 +15,7 @@ namespace DigitalData.MessagingService.Infrastructure.Queue;
 /// Provides message persistence, scalability, and reliability.
 /// Uses Lazy<T> initialization pattern to avoid blocking constructor.
 /// </summary>
-public sealed class OutgoingEmailConsumer(IOptions<RabbitMqConfiguration> config, ILogger<OutgoingEmailConsumer> Logger, IEmailService EmailService, RabbitMqConnectionFactory CnnFactory) : IOutgoingEmailConsumer, IAsyncDisposable
+public sealed class OutgoingEmailConsumer(IOptions<RabbitMqConfiguration> config, ILogger<OutgoingEmailConsumer> Logger, IEmailService EmailService, RabbitMqConnectionFactory CnnFactory) : IAsyncDisposable
 {
     private readonly RabbitMqConfiguration _config = config.Value;
     private IChannel? _consumeChannel = null;   // Dedicated channel for consuming