[led] No way to test devicelab tests on PR with engine changes #168997
Description
I was unable to test the relanding ( #168914 ) of a reverted PR that broke in post-submit devicelab tests.
led invocations seem to want a prebuilt engine.
I attempted the following invocation and it ran the text, but the logs don't show the engine being built so I don't think it is doing a proper test:
led get-builder "luci.flutter.try:Mac_ios channels_integration_test_ios" | led edit -pa git_ref='refs/pull/168914/head' | led edit -pa git_url='https://github.com/flutter/flutter' | led edit -pa is_fusion='true' | led edit -pa flutter_prebuilt_engine_version='0c2684c432e064cd79dd8ba0435a070b6d56f595' | led edit -pa flutter_realm='flutter_archives_v2' | led launch