core/types: fix LatestSignerForChainID panic with chainID 0

[hero5512]

LatestSignerForChainID was panicking when called with chainID 0 because it tried to create a modern signer which requires chainID > 0. Legacy transactions with chainID 0 should use HomesteadSigner instead.

Fixes panic when trying to get the signer of legacy transactions #32582

[lightclient]

Will let others chime in, but I think this is expected. We want to avoid users signing unprotected transactions. If you really need to do so, you can use the Homestead signer directly. I'm not sure we want to change the behavior.

[kevink1103]

@lightclient

go-ethereum/core/types/transaction.go

Lines 282 to 287 in 046e2cd

	// ChainId returns the EIP155 chain ID of the transaction. The return value will always be
	// non-nil. For legacy transactions which are not replay-protected, the return value is
	// zero.
	func (tx *Transaction) ChainId() *big.Int {
	return tx.inner.chainID()
	}

according to the comment, a legacy tx's chainID can technically be considered as zero and this fix is in line with the comment. what do you think?