samples: fix blink readme #792

Job	Run time
Build and package cores	8m 36s
Split off zephyr_contrib	9s
Split off zephyr	16s
Split off zephyr_main	14s
Split off zephyr_unoq	15s
Test zephyr_main:nano33ble	2m 35s
Test zephyr_main:giga	2m 28s
Test zephyr_main:niclasense	2m 27s
Test zephyr_main:opta	2m 28s
Test zephyr_main:portentac33	2m 30s
Test zephyr_main:portentah7	1m 57s
Test zephyr:unoq	2m 18s
Test zephyr_contrib:frdm_rw612	2m 24s
Test zephyr_contrib:frdm_mcxn947	2m 23s
Test zephyr_contrib:ek_ra8d1	2m 19s
Collect logs	7s
Publish core	13s
Publish jsons	20s
verify-core	0s
cleanup-artifacts	3s
	34m 2s

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