Exit with error code when user is not logged in

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=226390329

java/google/registry/tools/RegistryCli.java

@@ -170,6 +170,7 @@ final class RegistryCli implements AutoCloseable, CommandRunner {
         System.err.println("===================================================================");
         System.err.println("You must login using 'nomulus login' prior to running this command.");
         System.err.println("===================================================================");
+        System.exit(1);
       } else {
         throw ex;
       }