Summary:
Switch to using an env var since `bazel query` doesn't evaluate selects
and instead generate all branches which fails the OSS build.

Test Plan: Jenkins

Reviewers: zasgar

Reviewed By: zasgar
Signed-off-by: Vihang Mehta <vihang@pixielabs.ai>

Differential Revision: https://phab.corp.pixielabs.ai/D10048

GitOrigin-RevId: 00767181cd3d50962ffbbefda76d2220d9a4df52