fix: don't start HTTP tracker if it's disabled

This fixes this error:

```
Loading default configuration file: `./share/default/config/tracker.development.sqlite3.toml` ...
2024-01-19T12:43:24.605765751+00:00 [torrust_tracker::bootstrap::logging][INFO] logging initialized.
2024-01-19T12:43:24.606305647+00:00 [torrust_tracker::bootstrap::jobs::http_tracker][INFO] Note: Not loading Http Tracker Service, Not Enabled in Configuration.
2024-01-19T12:43:24.606314967+00:00 [torrust_tracker::bootstrap::jobs][INFO] TLS not enabled
thread 'tokio-runtime-worker' panicked at src/servers/registar.rs:84:32:
it should receive the listing: RecvError(())
```

src/app.rs

@@ -76,6 +76,10 @@ pub async fn start(config: &Configuration, tracker: Arc<core::Tracker>) -> Vec<J
 
     // Start the HTTP blocks
     for http_tracker_config in &config.http_trackers {
+        if !http_tracker_config.enabled {
+            continue;
+        }
+
         if let Some(job) = http_tracker::start_job(
             http_tracker_config,
             tracker.clone(),

src/servers/apis/server.rs

@@ -30,7 +30,7 @@ use axum_server::tls_rustls::RustlsConfig;
 use axum_server::Handle;
 use derive_more::Constructor;
 use futures::future::BoxFuture;
-use log::{error, info};
+use log::{debug, error, info};
 use tokio::sync::oneshot::{Receiver, Sender};
 use torrust_tracker_configuration::AccessTokens;
 
@@ -120,7 +120,12 @@ impl ApiServer<Stopped> {
         let launcher = self.state.launcher;
 
         let task = tokio::spawn(async move {
-            launcher.start(tracker, access_tokens, tx_start, rx_halt).await;
+            debug!(target: "API", "Starting with launcher in spawned task ...");
+
+            let _task = launcher.start(tracker, access_tokens, tx_start, rx_halt).await;
+
+            debug!(target: "API", "Started with launcher in spawned task");
+
             launcher
         });
 
@@ -266,9 +271,10 @@ mod tests {
     #[tokio::test]
     async fn it_should_be_able_to_start_and_stop() {
         let cfg = Arc::new(ephemeral_mode_public());
-        let tracker = initialize_with_configuration(&cfg);
         let config = &cfg.http_api;
 
+        let tracker = initialize_with_configuration(&cfg);
+
         let bind_to = config
             .bind_address
             .parse::<std::net::SocketAddr>()

src/servers/registar.rs

@@ -5,6 +5,7 @@ use std::net::SocketAddr;
 use std::sync::Arc;
 
 use derive_more::Constructor;
+use log::debug;
 use tokio::sync::Mutex;
 use tokio::task::JoinHandle;
 
@@ -81,10 +82,15 @@ impl Registar {
 
     /// Inserts a listing into the registry.
     async fn insert(&self, rx: tokio::sync::oneshot::Receiver<ServiceRegistration>) {
-        let listing = rx.await.expect("it should receive the listing");
+        debug!("Waiting for the started service to send registration data ...");
+
+        let service_registration = rx
+            .await
+            .expect("it should receive the service registration from the started service");
 
         let mut mutex = self.registry.lock().await;
-        mutex.insert(listing.binding, listing);
+
+        mutex.insert(service_registration.binding, service_registration);
     }
 
     /// Returns the [`ServiceRegistry`] of services