chore: remove unused op-reth repo (#981) #320

Job	Run time
reth (linux/amd64, ubuntu-24.04, jemalloc,asm-keccak,optimism)	24m 13s
geth (linux/arm64, ubuntu-24.04-arm)	3m 13s
geth (linux/amd64, ubuntu-24.04)	4m 16s
nethermind (linux/arm64, ubuntu-24.04-arm)	3m 39s
reth (linux/arm64, ubuntu-24.04-arm, jemalloc,optimism)	22m 10s
nethermind (linux/amd64, ubuntu-24.04)	3m 25s
merge-nethermind	34s
merge-geth	30s
merge-reth	29s
	1h 2m 29s

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