Add permit functions for flashblocks number contract

[avalonche]

📝 Summary

permit calls to flashblocks number contract if flashtestations are enabled as well. default to regular flashblocks number contract if flashtestations are not enabled.

--flashblocks.flashblocks-number-contract-use-permit flag to enable.

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✅ I have completed the following steps:

• Run make lint
• Run make test
• Added tests (if applicable)

[SozinM]

Let's add docs
Will this function just returns current flashblock number? If so why does it needs mutable ref to state?

[avalonche]

getting the tx nonce needs mutable ref. pub fn get_nonce(
db: &mut State,
address: Address,
) -> Result<u64, BuilderTransactionError> {
db.load_cache_account(address)
.map(|acc| acc.account_info().unwrap_or_default().nonce)
.map_err(|_| BuilderTransactionError::AccountLoadFailed(address))
}

[avalonche]

not sure if there's a way to do evm.transact without a signed tx?

[avalonche]

then the read only contract calls only need the call data

[SozinM]

If you want this to be not mutable - you need to use basic_ref function (that implemented for DatabaseRef)