🐛 [#4980] Add empty string to list of choices to account for an unfil…

…led field

Non-required fields can be empty upon submission, so need to include an empty string.

src/openforms/formio/components/vanilla.py

@@ -764,6 +764,7 @@ def as_json_schema(component: SelectComponent) -> JSONObject:
         label = component.get("label", "Select")
 
         choices = [options["value"] for options in component["data"]["values"]]
+        choices.append("")  # Take into account an unfilled field
 
         base = {"type": "string", "enum": choices}
         if multiple:
@@ -845,6 +846,8 @@ def as_json_schema(component: RadioComponent) -> JSONObject:
         label = component.get("label", "Radio")
 
         choices = [options["value"] for options in component["values"]]
+        choices.append("")  # Take into account an unfilled field
+
         base = {"title": label, "type": "string", "enum": choices}
 
         return base