ethermintd dose not support PubkeyMultisigThreshhold

[xiangjianmeng]

System info:

1. The anteHandler of cosmos simulation app usesDefaultSigVerificationGasConsumer which supports PubkeyMultisigThreshhold. But why the ethermint uses customized sigGasConsumer which does not support PubkeyMultisigThreshhold.

Steps to reproduce:

1. [First Step]
2. [Second Step]
3. [and so on...]

Expected behavior: [What you expected to happen]

Actual behavior: [What actually happened]

Additional info: [Include gist of relevant config, logs, etc.]

[fedekunze]

Correct, it doesn't support the default multisigs from the SDK as they are composed of secp256k1 keys which are not supported by the EVM module. There are 2 main options for how to address this:

1. Add support for this key type and the default SDK multisig but that would mean that a multisig couldn't be used on for EVM module
2. Write an ADR that proposes a custom multisig for eth_secp256k1 keys and implement it