fix(nix/buildkite): Disable `depends_on` if build phase is not run r/4221

Extra steps that use `depends_on` (e.g. if they need output from their
parent) should not actually depend on their parents build step if the
build phase is not active.

This is required to actually decouple the phases.

Change-Id: I398da9a8a53e97ca3c635342259fc722d54b8e4a
Reviewed-on: https://cl.tvl.fyi/c/depot/+/5829
Tested-by: BuildkiteCI
Reviewed-by: ezemtsov <eugene.zemtsov@gmail.com>

0 files changed, 0 insertions, 0 deletions