Issue #3248929 by kunal.sachdev: List update that will be applied on the UpdateReady form

...anager_test_fixture/package_manager_test_fixture.info.yml

...er_test_fixture/package_manager_test_fixture.services.yml

...anager_test_fixture/src/EventSubscriber/FixtureStager.php

src/Form/UpdateReady.php

tests/fixtures/staged/9.8.1/composer.json

tests/fixtures/staged/9.8.1/vendor/composer/installed.json

tests/src/Functional/AutomaticUpdatesFunctionalTestBase.php

tests/src/Functional/ReadinessValidationTest.php

tests/src/Functional/UpdateLockTest.php

tests/src/Functional/UpdaterFormTest.php