Requirements hook needs #[LegacyRequirementsHook] attribute

Problem/Motivation

There's a downstream test deprecation notice:

2) /var/www/html/docroot/core/lib/Drupal/Core/Hook/HookCollectorPass.php:640
webform_requirements without a #[LegacyRequirementsHook] attribute is deprecated in drupal:11.3.0 and removed in drupal:13.0.0. See https://www.drupal.org/node/3549685

Presumably, this hook needs the appropriate attribute added to it.

Steps to reproduce

Run downstream tests that rely on this module and observe deprecation notices being emitted.

Proposed resolution

1. Create an OOP hook (splitting into hook_runtime_requirements and hook_update_requirements).
2. Add the attribute.

Remaining tasks

• Add the attribute
• Review
• Merge
• Release
• Profit

User interface changes

None

API changes

None

Data model changes

None