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)

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