improve: marking long running tests as integration test #5867

Job	Run time
sample_operators_tests (sample-operators/webpage)	3m 6s
sample_operators_tests (sample-operators/tomcat-operator)	3m 26s
sample_operators_tests (sample-operators/mysql-schema)	3m 4s
sample_operators_tests (sample-operators/leader-election)	3m 31s
	13m 7s

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