Cleanup remains of ServiceMsg (#9236)

* Remove ServiceMsgClientConn from CLI

* Cleanup Operations

* Remove some legacytx.LegacyMsg

* Update CL

* Remove mentions of ServiceMsg

* Simply reflection MsgDescriptor

* Simplify more

* Add code comment

Co-authored-by: technicallyty <48813565+technicallyty@users.noreply.github.com>

types/msgservice/service_msg_client.go

@@ -1,47 +0,0 @@
-package msgservice
-
-import (
-	"context"
-	"fmt"
-
-	gogogrpc "github.com/gogo/protobuf/grpc"
-	grpc "google.golang.org/grpc"
-
-	sdk "github.com/cosmos/cosmos-sdk/types"
-)
-
-var _ gogogrpc.ClientConn = &ServiceMsgClientConn{}
-
-// ServiceMsgClientConn is an instance of grpc.ClientConn that is used to test building
-// transactions with MsgClient's. It is intended to be replaced by the work in
-// https://github.com/cosmos/cosmos-sdk/issues/7541 when that is ready.
-type ServiceMsgClientConn struct {
-	msgs []sdk.Msg
-}
-
-// Invoke implements the grpc ClientConn.Invoke method
-func (t *ServiceMsgClientConn) Invoke(_ context.Context, _ string, args, _ interface{}, _ ...grpc.CallOption) error {
-	req, ok := args.(sdk.Msg)
-	if !ok {
-		return fmt.Errorf("%T should implement %T", args, (*sdk.Msg)(nil))
-	}
-
-	err := req.ValidateBasic()
-	if err != nil {
-		return err
-	}
-
-	t.msgs = append(t.msgs, req)
-
-	return nil
-}
-
-// NewStream implements the grpc ClientConn.NewStream method
-func (t *ServiceMsgClientConn) NewStream(context.Context, *grpc.StreamDesc, string, ...grpc.CallOption) (grpc.ClientStream, error) {
-	return nil, fmt.Errorf("not supported")
-}
-
-// GetMsgs returns ServiceMsgClientConn.msgs
-func (t *ServiceMsgClientConn) GetMsgs() []sdk.Msg {
-	return t.msgs
-}