fix(nodebuilder/da): add handling for empty submit options

This change ensures that if the options byte slice is empty, the parseOptions function returns an empty slice of ConfigOption without proceeding to unmarshal. This prevents potential errors and enhances the function's robustness.

nodebuilder/da/service.go

@@ -153,18 +153,23 @@ func (s *Service) SubmitWithOptions(
 }
 
 func parseOptions(options []byte) ([]state.ConfigOption, error) {
+	var opts []state.ConfigOption
+
 	parsedOpts := struct {
 		KeyName           string
 		SignerAddress     string
 		FeeGranterAddress string
 	}{}
 
+	if len(options) == 0 {
+		return opts, nil
+	}
+
 	err := json.Unmarshal(options, &parsedOpts)
 	if err != nil {
 		return nil, err
 	}
 
-	var opts []state.ConfigOption
 	if parsedOpts.KeyName != "" {
 		opts = append(opts, state.WithKeyName(parsedOpts.KeyName))
 	}