79919 update BorderTween nullable (cla: yes, framework)

79953 Manually roll engine to 56b13559807bf4cb83d16c659757d6ae4f209490 (cla: yes, engine)

79959 Unblock roll by reverting #79061 (a: tests, cla: yes, framework, team)

79961 Mark integration_test_test as unflaky (cla: yes, team, waiting for tree to go green)

79968 Revert “Support block delete with word and line modifiers” (cla: yes, framework)

79973 Support block delete with word and line modifiers (cla: yes, framework)