Add disable txpool setting to OpEthApi

[mattsse]

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Describe the feature

ref #15759

we should mirror op-geth 1:1 on eth_sendrawtx:

https://github.com/ethereum-optimism/op-geth/blob/36501a7023fd85f3492a1af6f1474a0113bb83fe/eth/api_backend.go#L297-L299

hence we need a disable_txpool_admisson setting, similar to geth:

https://github.com/ethereum-optimism/op-geth/blob/36501a7023fd85f3492a1af6f1474a0113bb83fe/eth/ethconfig/config.go#L183-L183

on cli, like:

https://github.com/paradigmxyz/reth/blob/211ecb6d91064991d558d9ea4ae0b81c463304d7/crates/optimism/node/src/args.rs#L16-L18

but inverse:

https://github.com/ethereum-optimism/op-geth/blob/36501a7023fd85f3492a1af6f1474a0113bb83fe/cmd/utils/flags.go#L947-L951

TODO

• add CLI var mirroring geth
• add setting on OpEthApi https://github.com/paradigmxyz/reth/blob/211ecb6d91064991d558d9ea4ae0b81c463304d7/crates/optimism/rpc/src/eth/mod.rs#L280-L280
• apply check on setup: https://github.com/ethereum-optimism/op-geth/blob/36501a7023fd85f3492a1af6f1474a0113bb83fe/cmd/utils/flags.go#L1906-L1906, deriving disable_txpool based on what flags are set

Additional context

No response