28878 [Linux] Fix crash when a method channel is reassigned (cla: yes, waiting for tree to go green, platform-linux)

28879 Roll Skia from 31fe2c51452a to 496b89cb74b3 (4 revisions) (cla: yes, waiting for tree to go green)

28880 Roll Fuchsia Mac SDK from OPoARlWlE… to NxbeZ1Uke… (cla: yes, waiting for tree to go green)

28881 Roll Skia from 496b89cb74b3 to e96e066d538d (1 revision) (cla: yes, waiting for tree to go green)

28882 Roll Fuchsia Linux SDK from UUcoJDQho… to sFMn4Ory_… (cla: yes, waiting for tree to go green)