refactor!: Remove clientCtx.JSONCodec and rename EncodingConfig.Marshaler to Codec (#9521)

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## Description

Closes: #9499 

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- [ ] confirmed `!` in the type prefix if API or client breaking change
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server/export_test.go

@@ -136,7 +136,7 @@ func setupApp(t *testing.T, tempDir string) (*simapp.SimApp, context.Context, *t
 	serverCtx.Config.RootDir = tempDir
 
 	clientCtx := client.Context{}.WithCodec(app.AppCodec())
-	genDoc := newDefaultGenesisDoc(encCfg.Marshaler)
+	genDoc := newDefaultGenesisDoc(encCfg.Codec)
 
 	require.NoError(t, saveGenesisFile(genDoc, serverCtx.Config.GenesisFile()))
 	app.InitChain(

server/util_test.go

@@ -18,8 +18,8 @@ import (
 	"github.com/cosmos/cosmos-sdk/server"
 	"github.com/cosmos/cosmos-sdk/server/config"
 	"github.com/cosmos/cosmos-sdk/simapp"
-	genutilcli "github.com/cosmos/cosmos-sdk/x/genutil/client/cli"
 	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
+	genutilcli "github.com/cosmos/cosmos-sdk/x/genutil/client/cli"
 )
 
 var cancelledInPreRun = errors.New("Cancelled in prerun")
@@ -414,7 +414,7 @@ func TestEmptyMinGasPrices(t *testing.T) {
 	encCfg := simapp.MakeTestEncodingConfig()
 
 	// Run InitCmd to create necessary config files.
-	clientCtx := client.Context{}.WithHomeDir(tempDir).WithJSONCodec(encCfg.Marshaler)
+	clientCtx := client.Context{}.WithHomeDir(tempDir).WithCodec(encCfg.Codec)
 	serverCtx := server.NewDefaultContext()
 	ctx := context.WithValue(context.Background(), server.ServerContextKey, serverCtx)
 	ctx = context.WithValue(ctx, client.ClientContextKey, &clientCtx)