27796 [web] update TODO format to match flutter repo and fix names, more code cleanup (cla: yes, platform-web)

27815 [web] Code cleanup (cla: yes, platform-web)

27823 [web] Update CanvasPool documentation (cla: yes, platform-web, needs tests)

27836 Add GestureSettings and configure touch slop from Android ViewConfiguration (platform-android, cla: yes, waiting for tree to go green, platform-web, platform-fuchsia)

27879 Fix nullability of GestureSettings on ViewConfig (cla: yes, waiting for tree to go green, platform-web)

platform-fuchsia - 89 pull request(s)

20535 fuchsia: Delete unused compilation_trace code (cla: yes, waiting for tree to go green, platform-fuchsia)