Issue #3453682: Smart date always shows a label in Layout Builder even with no value

Closes #3453682

src/Plugin/Field/FieldType/SmartDateFieldItemList.php

@@ -190,7 +190,7 @@ class SmartDateFieldItemList extends DateTimeFieldItemList {
 
     // No default set, so nothing to do.
     if (empty($default_value[0]['default_date_type'])) {
-      return $default_value;
+      return [];
     }
 
     // A default date+time value should be in the format and timezone used