Remove GetSignBytes with Eden upgrade

[colin-axner]

Summary

GetSignBytes is being removed as an interface as apart of the Eden SDK upgrade. It can be removed after we have updated to SDK v0.50.x

Proposal

Remove GetSignBytes function from 29-fee msgs and transfer msgs. Please do this pr after the upgrade to SDK v0.50.x has occurred to reduce changes to review in the pr which bumps the SDK version

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[tac0turtle]

in 0.50 this is automatically inferred based off the proto name, but for backwards compatability we introduced a few proto annotations to recreate the same bytes as before.

Amino name annotation: https://github.com/cosmos/cosmos-sdk/blob/b990cb783a25fbcb9c95da570a7918ec29172514/proto/cosmos/auth/v1beta1/auth.proto#L15
Amino message encoding: https://github.com/cosmos/cosmos-sdk/blob/b990cb783a25fbcb9c95da570a7918ec29172514/proto/cosmos/auth/v1beta1/auth.proto#L35

We are working on documentation for this as well

[damiannolan]

Looks like there is some Route() and Type() methods on these msgs left hanging around. Should we remove them as well here? What do you think?

[tac0turtle]

they are not needed anymore

[damiannolan]

Indeed! Figured as much, thanks @tac0turtle

[damiannolan]

I'm not sure I understand what this documentation is recommending -> https://docs.cosmos.network/v0.50/core/encoding#authz-authorizations-and-govgroup-proposals

Should we be doing this amino codec registration on pkg init or is it not required?

[tac0turtle]

its not needed anymore, we still need to clean up docs for 0.50