Revert "YARN-9178. TestRMAdminCli#testHelp is failing in trunk. Contributed by Abhishek Modi."

This reverts commit 650b9cbe168da00966bebbe6fbdee5c1a9dbabb0.

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-client/src/test/java/org/apache/hadoop/yarn/client/cli/TestRMAdminCLI.java

@@ -812,7 +812,6 @@ public class TestRMAdminCLI {
               + "([OvercommitTimeout])] "
               + "[-transitionToActive [--forceactive] <serviceId>] "
               + "[-transitionToStandby <serviceId>] "
-              + "[-transitionToObserver <serviceId>] "
               + "[-getServiceState <serviceId>] [-getAllServiceState] "
               + "[-checkHealth <serviceId>] [-help [cmd]]";
       String actualHelpMsg = dataOut.toString();