samples: fix blink readme #794

Job	Run time
Build and package cores	9m 8s
Split off zephyr	11s
Split off zephyr_unoq	14s
Split off zephyr_main	9s
Split off zephyr_contrib	15s
Test zephyr_main:portentah7	2m 25s
Test zephyr:unoq	2m 24s
Test zephyr_main:niclasense	1m 50s
Test zephyr_main:giga	2m 42s
Test zephyr_main:portentac33	2m 29s
Test zephyr_main:opta	2m 29s
Test zephyr_main:nano33ble	2m 28s
Test zephyr_contrib:frdm_mcxn947	2m 0s
Test zephyr_contrib:ek_ra8d1	1m 48s
Test zephyr_contrib:frdm_rw612	2m 26s
Publish jsons	20s
Collect logs	9s
Publish core	0s
verify-core	-1s
cleanup-artifacts	5s
	33m 31s

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