OZG-4870 check if smtpServer is null

ozgcloud-keycloak-operator/src/main/java/de/ozgcloud/operator/keycloak/realm/KeycloakRealmMapper.java

@@ -54,7 +54,9 @@ interface KeycloakRealmMapper {
 	
 	@Named("smtpServer")
 	 default Map<String, String> mapSmtpServer(OzgCloudKeycloakRealmSpec.KeycloakRealmSMTPServer server) {
+		
 		Map<String, String> smtpServer = new HashMap<>();
+		if( server != null ) {
 			if( server.getHost() != null )
 				smtpServer.put("host", server.getHost());
 			if( server.getPort() != null )
@@ -71,7 +73,9 @@ interface KeycloakRealmMapper {
 				smtpServer.put("from", server.getFrom()); 
 			if( server.getFromDisplayName() != null ) 
 				smtpServer.put("fromDisplayName", server.getFromDisplayName()); 
+		}
 		return smtpServer;
+		
 	}
 
 }