Code review comment for lp:~sbaldassin/ubuntu-system-tests/fix_launch_app_from_scope

This change also affects open_preview, add this tests to execute:

ubuntu_system_tests.tests.test_uninstall_application.UninstallApplicationTestCase.test_uninstall_application

also affects go_to_store function, so add:
ubuntu_system_tests.tests.test_app_store.AppStoreTestCase.test_install_free_app