69736 Methods in build_ios_framework for universal and XCFrameworks (a: existing-apps, cla: yes, platform-ios, tool, waiting for tree to go green)

69749 Roll Engine from 59b01e0e5a3f to c7391d6b12c3 (12 revisions) (cla: yes, waiting for tree to go green)

69761 Link the API docs on waitFor() to the docs for runUnsynchronized() (a: tests, cla: yes, framework)

69781 Added dartpad examples for SliverAppBar (adopt a widget, cla: yes, d: api docs, d: examples, documentation, f: material design, framework, team, waiting for tree to go green)

69783 Reduce refresh indicator pull-down distance (cla: yes, f: material design, framework)