Support Amino Message type in ts-client

[akkien]

I create a new module that uses multisigned transactions. I try to follow example here to sign my transaction, but fail: https://github.com/cosmos/cosmjs/blob/main/packages/stargate/src/multisignature.spec.ts#L171

I think the problem is the way I convert Direct message (generated by Ignite) to Amino message (I created myself) is wrong. I checked the ts-client that is generated by Ignite and do not see Amino type for my message. Why Ignite only generate Direct type message and not Amino type?