[SHIBUI-1029]

Added a filter to remove admins that have no email addressees from the
new user email sending.

backend/src/main/java/edu/internet2/tier/shibboleth/admin/ui/service/EmailServiceImpl.java

@@ -2,6 +2,7 @@
 
 import edu.internet2.tier.shibboleth.admin.ui.security.model.User;
 import edu.internet2.tier.shibboleth.admin.ui.security.repository.UserRepository;
+import org.apache.commons.lang.StringUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.context.support.ResourceBundleMessageSource;
@@ -72,6 +73,6 @@ public String[] getSystemAdminEmailAddresses() {
             logger.warn("No users with ROLE_ADMIN were found! Check your configuration!");
             systemAdmins = new HashSet<>();
         }
-        return systemAdmins.stream().map(User::getEmailAddress).distinct().toArray(String[]::new);
+        return systemAdmins.stream().filter(user -> StringUtils.isNotBlank(user.getEmailAddress())).map(User::getEmailAddress).distinct().toArray(String[]::new);
     }
 }