Tracking issue for tasks associated with removing the defaultValue parameter from Stream.firstWhere and Stream.lastWhere.

TODO

• Deprecate
• Fixup package:async:
  • Fixes: Deprecate DelegatingStream.typed and make it delegate to Stream.cast dart-archive/async#54
  • Roll to SDK
  • Roll internal
• Fixup package:shuttlecock
  • Roll internal
• Fix additional packages (add here)
• Roll packages (add here)
• Fix internal
• Land in SDK
  • Follow up on breaking change
  • Roll flutter
  • Roll internal

cc @lrhn @keertip @srawlins @anders-sandholm @vsmenon @dgrove