DomainConfigEditContextTest fatals on Drupal 10: imports the Drupal 11.1+ DeprecationBridge ExpectDeprecationTrait

Spotted while running the previous-major (Drupal 10) test lane on #3592825.

Problem

DomainConfigEditContextTest (added in #3592832) imports Drupal\TestTools\Extension\DeprecationBridge\ExpectDeprecationTrait, which only exists in Drupal 11.1 and later. On Drupal 10.x that trait does not exist, so the class-body use statement fatals at class load:

PHP Fatal error: Trait "Drupal\TestTools\Extension\DeprecationBridge\ExpectDeprecationTrait" not found

Because the kernel test cannot load, it brings down the whole previous-major phpunit job, blocking that lane for every merge request targeting 3.x (the module declares ^10.2 || ^11).

Proposed resolution

Resolve the trait across both majors. Drupal 10.x provides Drupal\Tests\Traits\ExpectDeprecationTrait; Drupal 11.1+ provides the DeprecationBridge one and drops the old name. Alias the legacy trait to the new name when only the legacy one is present, so the test loads on both:

if (!trait_exists(ExpectDeprecationTrait::class)
  && trait_exists('Drupal\Tests\Traits\ExpectDeprecationTrait')) {
  class_alias('Drupal\Tests\Traits\ExpectDeprecationTrait', ExpectDeprecationTrait::class);
}

Remaining tasks

• Add the cross-version alias before the class declaration.
• Confirm the kernel test passes on Drupal 10 and Drupal 11.