fix: Add RegisterLegacyAminoCodec for authz/feegrant

[amaury1093]

Description

Closes: #11190

---

Author Checklist

All items are required. Please add a note to the item if the item is not applicable and
please add links to any relevant follow up issues.

I have...

• included the correct type prefix in the PR title
• added ! to the type prefix if API or client breaking change
• targeted the correct branch (see PR Targeting)
• provided a link to the relevant issue or specification
• followed the guidelines for building modules
• included the necessary unit and integration tests
• added a changelog entry to CHANGELOG.md
• included comments for documenting Go code
• updated the relevant documentation or specification
• reviewed "Files changed" and left comments if necessary
• confirmed all CI checks have passed

Reviewers Checklist

All items are required. Please add a note if the item is not applicable and please add
your handle next to the items reviewed if you only reviewed selected items.

I have...

• confirmed the correct type prefix in the PR title
• confirmed ! in the type prefix if API or client breaking change
• confirmed all author checklist items have been addressed
• reviewed state machine logic
• reviewed API design and naming
• reviewed documentation is accurate
• reviewed tests and test coverage
• manually tested (if applicable)

[RiccardoM]

Just a reminder: there is also the need to implement Amino serialization for the Authorization interface and all its implementations. Also the Amino codec needs to be created and used when serializing the messages (same as what happens inside other modules). If you want I can help you with that tomorrow @AmauryM

[amaury1093]

Note: for nested Msgs, Amino doesn't show their type/value pair. That's because we use a local ModuleCdc to do msg.GetSignBytes, and this local ModuleCdc isn't aware of other modules' amino registrations. I think it's fine, as long as the top-level Msg has a type/value.

[amaury1093]

@RiccardoM Oh yeah, that sounds good! I have some other work to do on gov/group, so would love if you can finish this PR. (Feel free to push here, or close it and open a new one if you want)

[RiccardoM]

@AmauryM Created #11224 which implements everything