Revert using a global `legacy.Cdc` for all modules

[amaury1093]

Summary of Bug

Revert using a global legacy.Cdc for all modules

Version

v0.46.0-beta2

Steps to Reproduce

In #11240, we removed each module's individual ModuleCdc, and instead used one single legacy.Cdc for amino sigining. It removed n globals, replacing by one single one, and at the same time fixed #11190.

However, it seems that other chains are using the singleton legacy.Cdc in ways that lead to errors (double registration). We decided to revert this change.

Proposal

• Revert feat: replace all ModuleCdc instances with legacy.Cdc #11240 and fix: implement Amino serialization for x/authz and x/feegrant #11224
• To make sure x/authz and x/feegrant don't support ledger signing #11190 is still fixed, create a new ModuleCdc in authz. Register this authz.ModuleCdc in all modules' RegisterLegacyAminoCodec.

cc @RiccardoM

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[robert-zaremba]

However, it seems that other chains are using the singleton legacy.Cdc in ways that lead to errors (double registration).

It sounds like this other chains found a hacky workaround for their own use cases. TBH, it would be better to clearly state and provide a migration path rather than keeping "half" registered codec instances.

[alexanderbez]

Why do we still keep the global legacy.Cdc around again?

[robert-zaremba]

Why do we still keep the global legacy.Cdc around again?

Some other chains are relaying on that :(