Added missing registration of IAzureBlobStorage interface which had b… (#1628)

# Description

The IAzureBlobStorage interface had been moved from the Jobs area into
Core as it was reusable. It had not been registered within core, so was
causing a failure of the app during the dependency injection process.

# Checklist:

- [ ] My work is behind a feature toggle (if appropriate)
- [ ] If my work is behind a feature toggle, I've added a full suite of
tests for both the ON and OFF state
- [ ] The ticket number is in the Pull Request title, with format
"APPT-XXX: My Title Here"
- [ ] I have ran npm tsc / lint (in the future these will be ran
automatically)
- [ ] My code generates no new .NET warnings (in the future these will
be treated as errors)
- [ ] If I've added a new Function, it is disabled in all but one of the
terraform groups (e.g. http_functions)
- [ ] If I've added a new Function, it has both unit and integration
tests. Any request body validators have unit tests also
- [ ] If I've made UI changes, I've added appropriate Playwright and
Jest tests
- [ ] If I've added/updated an end-point, I've added the appropriate
annotations and tested the Swagger documentation reflects the change

Author: SimonHarropNHS

src/api/Nhs.Appointments.Core/Concurrency/ServiceRegistration.cs

@@ -1,5 +1,6 @@
-using Nhs.Appointments.Core.Concurrency;
 using Microsoft.Extensions.Azure;
+using Nhs.Appointments.Core.Blob;
+using Nhs.Appointments.Core.Concurrency;
 
 namespace Microsoft.Extensions.DependencyInjection;
 
@@ -17,12 +18,14 @@ public static IServiceCollection AddAzureBlobStoreLeasing(this IServiceCollectio
             opts.Timeout = TimeSpan.FromSeconds(30);
             opts.ContainerName = containerName;
         });
-
+                    
         services.AddAzureClients(x =>
         {
             x.AddBlobServiceClient(connectionString);
         });
 
-        return services.AddSingleton<ISiteLeaseManager, AzureStorageSiteLeaseManager>();
+        return services
+            .AddSingleton<IAzureBlobStorage, AzureBlobStorage>()
+            .AddSingleton<ISiteLeaseManager, AzureStorageSiteLeaseManager>();
     }
 }