Deprecated function error

Problem/Motivation

This error appears on node save and content type save:

Deprecated function: Calling static trait method Drupal\textfield_counter\Plugin\Field\FieldWidget\TextFieldCounterWidgetTrait::getLengthOfSubmittedValue is deprecated, it should only be called on a class using the trait in Drupal\textfield_counter\Plugin\Field\FieldWidget\TextFieldCounterWidgetTrait::validateFieldFormElement() (line 352 of modules/contrib/textfield_counter/src/Plugin/Field/FieldWidget/TextFieldCounterWidgetTrait.php).

Steps to reproduce

1. Enable the counter on a textarea
2. Save the content type - error appears
3. Create a node containing the textarea with counter field - error appears

Tested with Drupal 9.5.9 and textfield counter 2.1.0