fix: Fix null reference exception in the RegisterOrganization mutation

src/VirtoCommerce.ProfileExperienceApiModule.Data/Commands/RegisterRequestCommandHandler.cs

@@ -104,7 +104,7 @@ private async Task<RegisterOrganizationResult> ProcessRequestAsync(RegisterReque
                 _organizationValidator.ValidateAsync(organization)
             };
 
-            foreach (var address in organization.Addresses)
+            foreach (var address in organization?.Addresses ?? new List<Address>())
             {
                 validationTasks.Add(_addressValidator.ValidateAsync(address));
             }