21526 iOS: only add explicit transactions when there are platform views (only on main threads) (cla: yes, platform-ios, waiting for tree to go green)

21529 Roll Fuchsia Mac SDK from aO19K7Ut2… to U2Cd8uL4-… (cla: yes, waiting for tree to go green)

21533 Roll Fuchsia Linux SDK from sDtTSnOFx… to GEYgsTBRM… (cla: yes, waiting for tree to go green)

21534 [Android Text Input] Make the editing state listenable and allow batch edits  (affects: text input, cla: yes, platform-android, waiting for tree to go green)

21537 Roll Dart SDK from 0ed6ae6d709e to ddbeaabe8b3d (1 revision) (cla: yes, waiting for tree to go green)