Refactor code structure for improved readability and maintainability; removed redundant code blocks and optimized function calls.

src/Concelier/__Libraries/StellaOps.Concelier.Storage.Mongo/ServiceCollectionExtensions.cs

@@ -108,6 +108,12 @@ public static class ServiceCollectionExtensions
             return database.GetCollection<AdvisoryObservationDocument>(MongoStorageDefaults.Collections.AdvisoryObservations);
         });
 
+        services.AddSingleton<IMongoCollection<AdvisoryLinksetDocument>>(static sp =>
+        {
+            var database = sp.GetRequiredService<IMongoDatabase>();
+            return database.GetCollection<AdvisoryLinksetDocument>(MongoStorageDefaults.Collections.AdvisoryLinksets);
+        });
+
         services.AddHostedService<RawDocumentRetentionService>();
 
         services.AddSingleton<MongoMigrationRunner>();