Issue #3557282 by dydave: Fixed phpstan errors by using core utility...

David Suissarequested to merge
issue/admin_toolbar-3557282:3557282-fix-phpstan-errors into 3.x

https://www.drupal.org/project/admin_toolbar/issues/3557282

Automated testing on Gitlab CI:
Fixed PHPSTAN validation job errors by using core utility function NestedArray::mergeDeep() instead of directly changing link attributes options array.

See related commit: 62c44471

Merge request reports