improve: metrics processing e2e test stability #6651

Job	Run time
sample_operators_tests (sample-operators/webpage)	3m 0s
sample_operators_tests (sample-operators/metrics-processing)	7m 51s
sample_operators_tests (sample-operators/mysql-schema)	2m 54s
sample_operators_tests (sample-operators/tomcat-operator)	3m 2s
sample_operators_tests (sample-operators/leader-election)	3m 21s
	20m 8s

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