[Backport 2.12] added sleep for flaky tests

[riysaxen-amzn]

Issue 1381

*Added sleep of some 30s to fix integ Test failure -> https://build.ci.opensearch.org/blue/organizations/jenkins/integ-test/detail/integ-test/7884/pipeline/

java.lang.AssertionError: Unexpected status expected:<FORBIDDEN> but was:<NOT_FOUND>

        at __randomizedtesting.SeedInfo.seed([B335CFE7D740BC9:7370413AD3F31CC0]:0)

        at org.junit.Assert.fail(Assert.java:89)

        at org.junit.Assert.failNotEquals(Assert.java:835)

        at org.junit.Assert.assertEquals(Assert.java:120)

        at org.opensearch.alerting.resthandler.SecureMonitorRestApiIT.test create monitor with an user without index read role(SecureMonitorRestApiIT.kt:256)

CheckList:

• Commits are signed per the DCO using --signoff

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
For more information on following Developer Certificate of Origin and signing off your commits, please check here.

[AWSHurneyt]

Manual backport of PR #1436