65878 Revert “Add CompositedTransformFollower.{followerAnchor, leaderAnchor… (cla: yes, framework)

65880 migrate some cupertino files to nullsafety (cla: yes, f: cupertino, framework, waiting for tree to go green)

65883 Roll Engine from 3c9308faad0b to 770b143a855e (2 revisions) (cla: yes, waiting for tree to go green)

65884 Reland 64930 Add CompositedTransformFollower.{followerAnchor, leaderAnchor} for custom anchoring (cla: yes, framework, waiting for tree to go green)

65889 Roll Engine from 770b143a855e to 1cabedf8aca8 (1 revision) (cla: yes, waiting for tree to go green)