Fixed isNarrowScreen helper to not require specific element

doc/development/adding_service_component.md

doc/development/testing_guide/end_to_end/beginners_guide.md

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doc/development/testing_guide/end_to_end/best_practices.md

doc/development/testing_guide/end_to_end/feature_flags.md

doc/development/testing_guide/end_to_end/flows.md

doc/development/testing_guide/end_to_end/index.md

doc/development/testing_guide/end_to_end/page_objects.md

doc/development/testing_guide/end_to_end/resources.md

...de/end_to_end/running_tests_that_require_special_setup.md