Use googlesource cl for self testing.

led doesn't understand git.corp urls making the led unit tests fail.

Change-Id: I9d6f6cfa2f63c36cbc730712765abe368cc6836e
Bug: None
Test: CQ
Reviewed-on: https://flutter-review.googlesource.com/c/recipes/+/3780
Reviewed-by: Rob Mohr <mohrr@google.com>
Commit-Queue: Godofredo Contreras <godofredoc@google.com>