chore: remove test u8 check #4421

Job	Run time
clippy	1m 26s
check	19s
check no_std	20s
check serde	22s
check no_std optimism,kzg-rs	25s
check std	22s
docs	1m 15s
fmt	10s
TyposCheck	6s
test stable --no-default-features	1m 12s
test stable	1m 57s
test stable --all-features	2m 7s
test beta --no-default-features	53s
test beta	56s
test beta --all-features	1m 45s
test nightly --no-default-features	54s
test nightly	56s
test nightly --all-features	1m 23s
	16m 48s

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