fix: time unit in PeriodicCleanerExpectationManager and integration t… #6043

Job	Run time
sample_operators_tests (sample-operators/tomcat-operator)	2m 57s
sample_operators_tests (sample-operators/mysql-schema)	2m 39s
sample_operators_tests (sample-operators/webpage)	3m 1s
sample_operators_tests (sample-operators/leader-election)	3m 25s
	12m 2s

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