fix: Retrieve PDS Demographic - Correct Service Bus connection string handling in configuration

application/CohortManager/src/Functions/DemographicServices/RetrievePDSDemographic/Program.cs

@@ -25,7 +25,7 @@
     })
     .AddJwtTokenSigning(config.UseFakePDSServices)
     .AddTelemetry()
-    .AddServiceBusClient(config.ServiceBusConnectionString)
+    .AddServiceBusClient(config.EffectiveServiceBusConnectionString)
     .AddHttpClient(config.UseFakePDSServices)
     .Build();
 

application/CohortManager/src/Functions/DemographicServices/RetrievePDSDemographic/RetrievePDSDemographicConfig.cs

@@ -1,6 +1,7 @@
 namespace NHS.CohortManager.DemographicServices;
 
 using System.ComponentModel.DataAnnotations;
+using Microsoft.Extensions.Configuration;
 
 public class RetrievePDSDemographicConfig
 {
@@ -28,4 +29,28 @@ public class RetrievePDSDemographicConfig
 
     public required bool UseFakePDSServices { get; set; } = false;
     public string ClientId { get; set; } = string.Empty;
+
+    [ConfigurationKeyName("ServiceBusConnectionString_client_internal")]
+    public string? ServiceBusConnectionStringClientInternal { get; set; }
+
+    [Required]
+    public string EffectiveServiceBusConnectionString
+    {
+        get
+        {
+            if (!string.IsNullOrWhiteSpace(ServiceBusConnectionString))
+            {
+                return ServiceBusConnectionString;
+            }
+
+            if (!string.IsNullOrWhiteSpace(ServiceBusConnectionStringClientInternal))
+            {
+                return ServiceBusConnectionStringClientInternal;
+            }
+
+            throw new InvalidOperationException(
+                "Missing Service Bus connection string. " +
+                "Set ServiceBusConnectionString or ServiceBusConnectionString_client_internal.");
+        }
+    }
 }