test: enhance `findFreePort` E2E utility reliability and clarity #2644

Job	Run time
list	23s
workflow (modules-builder-tests)	1m 46s
workflow (devkit-core-tests)	1m 17s
workflow (build-unit-tests)	2m 17s
workflow (devkit-core-tests-rerun)	1m 23s
workflow (build-cli)	1m 48s
	8m 54s

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