27226 [fuchsia] make dart_runner work with cfv2 (cla: yes, platform-fuchsia, needs tests)

27241 Migrate non-scenic-based fuchsia tests to cfv2. (affects: tests, cla: yes, platform-fuchsia, tech-debt)

27327 fuchsia: Update SessionConnection & tests w/ FakeScenic (affects: tests, cla: yes, platform-fuchsia, tech-debt)

27330 [fuchsia] Cleanup unused method in dart:zircon handle (cla: yes, waiting for tree to go green, platform-fuchsia, needs tests)

27347 Do not use the centralized graphics context options for Fuchsia Vulkan contexts (cla: yes, waiting for tree to go green, platform-fuchsia, needs tests)