Issue #3431256 by junkuncz: Fix phpstan issues in 3.x CI build.

.gitlab-ci.yml

...es/custom_elements_ui/src/CustomElementsUiPermissions.php

...ments_ui/src/Form/EntityCustomElementsDisplayEditForm.php

...ts_ui/src/Plugin/Derivative/CustomElementsUiLocalTask.php

src/CustomElement.php

src/CustomElementsConfigGenerator.php

src/Processor/DefaultContentEntityProcessor.php

tests/src/Functional/CustomElementsRenderMarkupTest.php

tests/src/Functional/CustomElementsRenderMarkupVue3Test.php