FieldType DecimalItem may fail with a TypeError in preSave

Appears to be missing steps section of the template.

Change appears small but wonder if a simple assertion for test coverage can be added.

I've added the steps to reproduce, not sure if I can also do the tests. Would be great if someone could help with that.

Tested this in drupal 11.2-dev with php 8.3.12. This seems to work fine with the code provided in the steps. I also tried the way as below and I could see the node getting saved without issues

        $node = \Drupal::entityTypeManager()->getStorage('node')->load(7);
        $node->set('field_decimal1', (string) "13.5");
        $node->save();