chore: revert making constructors private

Author: taefi

packages/java/endpoint/src/main/java/com/vaadin/hilla/signals/operation/ValidationResult.java

@@ -25,12 +25,12 @@ public enum Status {
     private final Status status;
     private final String errorMessage;
 
-    private ValidationResult(Status status, String errorMessage) {
+    public ValidationResult(Status status, String errorMessage) {
         this.status = status;
         this.errorMessage = errorMessage;
     }
 
-    private ValidationResult(Status status) {
+    public ValidationResult(Status status) {
         this.status = status;
         this.errorMessage = null;
     }