Use generate instead of empty

Author: PolPinol

src/main/java/io/autoinvestor/domain/model/UserId.java

@@ -14,8 +14,4 @@ public static UserId generate() {
     public static UserId from(String id) {
         return new UserId(id);
     }
-
-    public static UserId empty() {
-        return new UserId("");
-    }
 }

src/main/java/io/autoinvestor/domain/model/UserState.java

@@ -12,7 +12,7 @@ public record UserState(
         Date updatedAt
 ) {
     public static UserState empty() {
-        return new UserState(UserId.empty(), FirstName.empty(), LastName.empty(), UserEmail.empty(), RiskLevel.empty(), new Date(), new Date());
+        return new UserState(UserId.generate(), FirstName.empty(), LastName.empty(), UserEmail.empty(), RiskLevel.empty(), new Date(), new Date());
     }
 
     public UserState withUserCreated(UserWasRegisteredEvent event) {