[fix][cli] Fix logging noise while admin tool exit

[rdhabalia]

Motivation

Pulsar admin tool unnecessary logs noise while existing the process which gives bad user experience and should be removed.

./bin/pulsar-admin topics list test1/test2               
null

Reason: java.util.concurrent.CompletionException: org.apache.pulsar.client.admin.internal.http.AsyncHttpConnector$RetryException: Could not complete the operation. Number of retries has been exhausted. Failed reason: Connection refused: localhost/127.0.0.1:8080
2023-03-21T17:53:57,334-0700 [main] WARN  org.apache.pulsar.common.util.ShutdownUtil - Triggering immediate shutdown of current process with status 1
java.lang.Exception: Stacktrace for immediate shutdown
	at org.apache.pulsar.common.util.ShutdownUtil.triggerImmediateForcefulShutdown(ShutdownUtil.java:55) ~[pulsar-common-3.0.0-SNAPSHOT.jar:3.0.0-SNAPSHOT]
	at org.apache.pulsar.common.util.ShutdownUtil.triggerImmediateForcefulShutdown(ShutdownUtil.java:50) ~[pulsar-common-3.0.0-SNAPSHOT.jar:3.0.0-SNAPSHOT]
	at org.apache.pulsar.admin.cli.PulsarAdminTool.exit(PulsarAdminTool.java:315) ~[pulsar-client-tools.jar:3.0.0-SNAPSHOT]
	at org.apache.pulsar.admin.cli.PulsarAdminTool.execute(PulsarAdminTool.java:305) ~[pulsar-client-tools.jar:3.0.0-SNAPSHOT]
	at org.apache.pulsar.admin.cli.PulsarAdminTool.main(PulsarAdminTool.java:280) ~[pulsar-client-tools.jar:3.0.0-SNAPSHOT]

Verifying this change

• Make sure that the change passes the CI checks.

(Please pick either of the following options)

This change is a trivial rework / code cleanup without any test coverage.

(or)

This change is already covered by existing tests, such as (please describe tests).

(or)

This change added tests and can be verified as follows:

(example:)

• Added integration tests for end-to-end deployment with large payloads (10MB)
• Extended integration test for recovery after broker failure

Does this pull request potentially affect one of the following parts:

If the box was checked, please highlight the changes

• Dependencies (add or upgrade a dependency)
• The public API
• The schema
• The default values of configurations
• The threading model
• The binary protocol
• The REST endpoints
• The admin CLI options
• The metrics
• Anything that affects deployment

Documentation

• doc
• doc-required
• doc-not-needed
• doc-complete

Matching PR in forked repository

PR in forked repository:

[poorbarcode]

Since we will start the RC version of 3.0.0 on 2023-04-11, I will change the label/milestone of PR who have not been merged.

• The PR of type feature is deferred to 3.1.0
• The PR of type fix is deferred to 3.0.1

So drag this PR to 3.0.1

[nicoloboschi]

/pulsarbot rerun-failure-checks

[github-actions]

The pr had no activity for 30 days, mark with Stale label.

[tisonkun]

I like this change. Let me see if I can help nudge this patch.

[eolivelli]

Lgtm

I was about to send a similar patch

Thanks

[tisonkun]

Merging..

Thanks for taking care of this!