Update //third_party/dart_lang/v2 and macos_sdk to 2b4a84efd01e0d1cab8d00152bd8dee25aae4270.
Update //third_party/dart_lang/v2 and macos_sdk to 2b4a84efd01e0d1cab8d00152bd8dee25aae4270.

PiperOrigin-RevId: 270641671

angulardart/angular,angulardart/angular,angulardart/angular