[#1279] adm: Interpret "root" name as empty for namespace target type

Signed-off-by: Airat Arifullin <a.arifullin@yadro.com>

cmd/frostfs-adm/internal/modules/morph/ape/ape_util.go

@@ -38,6 +38,12 @@ var (
 func parseTarget(cmd *cobra.Command) policyengine.Target {
 	name, _ := cmd.Flags().GetString(targetNameFlag)
 	typ, err := parseTargetType(cmd)
+
+	// interpret "root" namespace as empty
+	if typ == policyengine.Namespace && name == "root" {
+		name = ""
+	}
+
 	commonCmd.ExitOnErr(cmd, "read target type error: %w", err)
 
 	return policyengine.Target{