refactor(core): move amino registrar and drop legacy package (backport #21531) (#21561)

Co-authored-by: Julien Robert <julien@rbrt.fr>

codec/legacy/amino_msg.go

@@ -3,7 +3,7 @@ package legacy
 import (
 	"fmt"
 
-	"cosmossdk.io/core/legacy"
+	"cosmossdk.io/core/registry"
 
 	sdk "github.com/cosmos/cosmos-sdk/types"
 )
@@ -11,9 +11,9 @@ import (
 // RegisterAminoMsg first checks that the msgName is <40 chars
 // (else this would break ledger nano signing: https://github.com/cosmos/cosmos-sdk/issues/10870),
 // then registers the concrete msg type with amino.
-func RegisterAminoMsg(cdc legacy.Amino, msg sdk.Msg, msgName string) {
+func RegisterAminoMsg(registrar registry.AminoRegistrar, msg sdk.Msg, msgName string) {
 	if len(msgName) > 39 {
 		panic(fmt.Errorf("msg name %s is too long to be registered with amino", msgName))
 	}
-	cdc.RegisterConcrete(msg, msgName)
+	registrar.RegisterConcrete(msg, msgName)
 }