[CI] Fix macos buildkite ci
Summary: macOS CI builds sometimes fails. This doesn't happen to the iOS build so it's probably the differences between macOS and iOS setup. This diff changes the macOS CI setup to work like the iOS one.
Test Plan: Check if buildkite CI works with this diff
Reviewers: atul, jon
Reviewed By: atul
Subscribers: ashoat, tomek
Differential Revision: https://phab.comm.dev/D7031