Pass the exception to HealthCheckEnd log message (#24786)

There was null intead of exception passed.

src/HealthChecks/HealthChecks/src/DefaultHealthCheckService.cs

@@ -254,7 +254,7 @@ namespace Microsoft.Extensions.Diagnostics.HealthChecks
                         break;
 
                     case HealthStatus.Unhealthy:
-                        _healthCheckEndUnhealthy(logger, registration.Name, duration.TotalMilliseconds, entry.Status, entry.Description, null);
+                        _healthCheckEndUnhealthy(logger, registration.Name, duration.TotalMilliseconds, entry.Status, entry.Description, entry.Exception);
                         break;
                 }
             }