[MM-54594] Adding new global relay type (#24672)

* adding new global relay type, custom

webapp/platform/types/src/config.ts

@@ -833,6 +833,8 @@ export type MessageExportSettings = {
         SMTPPassword: string;
         EmailAddress: string;
         SMTPServerTimeout: number;
+        CustomSMTPServerName: string;
+        CustomSMTPPort: string;
     };
 };