Fix a comment in MetadataTest.php

Author: RTLcoil

tests/MetadataTest.php

@@ -581,7 +581,7 @@ public function test_integer_field_validation()
             'default_value' => $metadata_field['default_value'],
         ]);
 
-        // Test entering a metadata field with integer validation and a valid default value
+        // Test entering a metadata field with integer validation and an invalid default value
         $metadata_field = [
             'external_id' => self::$external_id_int_validation_2,
             'label' => self::$external_id_int_validation_2,