Error if the entity ID is empty in drupalField() when using drupal_field()

Problem/Motivation

I got the next error

Argument 3 passed to Drupal\twig_tweak\TwigTweakExtension::drupalField() must be of the type string, null given, called in /vendor/twig/twig/src/Environment.php(418) : eval()'d code on line 42 in Drupal\twig_tweak\TwigTweakExtension::drupalField() (line 195 of modules/contrib/twig_tweak/src/TwigTweakExtension.php).

Steps to reproduce

I'm now quite sure when this happened. I was making module updates and core upgrade to 9. After the upgrade I tested the Webform and got the mentioned error. The Webform also uses AJAX and multistep.
I am using drupal_field() in a Webform and after the upgrade one of the fields that was prepopulated was indicated with no value.

Versions before and after update:

• Core 8.9.19 -> 9.2.8
• Webform 6.0.5 -> 6.1.0
• Twig Tweak 2.9.0 -> 3.1.3

Proposed resolution

I tried to add some conditions to it, but it didn't work. The only thing that did, is attached in the patch.

Maybe the solution is not intended for this module, because I saw in another issue, where is mentioned, that it's up to developer to make sure that drupal_field() gets a correct entity ID. But in my case it was not working. If my solution is not accepted, maybe will help somebody in my situation.