24249 Roll CanvasKit to 0.23 (cla: yes, platform-web)

24250 [flutter_releases] clarify comment (cla: yes)

24251 [flutter_releases] Pin the package_config package (cla: yes)

24252 Roll buildroot to 739be241578e7f12773eedb713df7fe3b0ec917b (cla: yes)

24253 Define FLUTTER_ENABLE_SKSHAPER consistently when building txt_unittests and txt_benchmarks (cla: yes, waiting for tree to go green)

24255 Roll Dart SDK from 8e4be6e4a496 to 9a16b6bca556 (3 revisions) (cla: yes, waiting for tree to go green)