Fix ShellOption with required

- Take 2
- Fix case with optional.
- Fixes #436

spring-shell-standard/src/main/java/org/springframework/shell/standard/StandardMethodTargetRegistrar.java

@@ -140,7 +140,7 @@ public class StandardMethodTargetRegistrar implements MethodTargetRegistrar, App
 									&& !ObjectUtils.nullSafeEquals(so.defaultValue(), ShellOption.NULL)) {
 								optionSpec.defaultValue(so.defaultValue());
 							}
-							else {
+							if (ObjectUtils.nullSafeEquals(so.defaultValue(), ShellOption.NONE)) {
 								optionSpec.required();
 							}
 						}