26655 Roll Dart SDK from 4dc4671c3a87 to a2ef55cfb8ac (1 revision) (cla: yes, waiting for tree to go green)

26656 Roll Skia from 6b2121d0ec57 to 43c713d5cd1a (5 revisions) (cla: yes, waiting for tree to go green)

26659 small clean-up of the license script (cla: yes, platform-web)

26661 Roll Dart SDK from a2ef55cfb8ac to b7c2babecc88 (1 revision) (cla: yes, waiting for tree to go green)

26662 Add test for CanvasKit text memory crash (cla: yes, platform-web)

26666 Updates the objectc docs script to use env variables. (cla: yes, waiting for tree to go green)