systemcmds: Add head to system commands #22507

Job	Run time
build (check_format)	1m 9s
build (tests)	5m 35s
build (tests_coverage)	6m 28s
build (px4_fmu-v2_default stack_check)	3m 29s
build (validate_module_configs)	49s
build (shellcheck_all)	1m 33s
build (NO_NINJA_BUILD=1 px4_fmu-v5_default)	4m 22s
build (NO_NINJA_BUILD=1 px4_sitl_default)	3m 10s
build (airframe_metadata)	1m 3s
build (module_documentation)	1m 12s
build (parameters_metadata)	1m 11s
	30m 1s

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