Enforce TrustedCallbackInterface in #date_date_callbacks

Problem/Motivation

#date_date_callbacks callbacks must be methods of a class that implements \Drupal\Core\Security\TrustedCallbackInterface or be an anonymous function. Support for this callback implementation is deprecated in drupal:9.3.0 and will be removed in drupal:10.0.0.

Steps to reproduce

Proposed resolution

Throw an exception when an untrusted date callback is encountered in Drupal 10.

Remaining tasks

User interface changes

API changes

Data model changes

Release notes snippet