Since Python packages are installed by GN now, packages are installed in
the correct order. This allows local deps to be fully expressed.

Change-Id: I057cc0902b16da3480f73520281eb52391236a63
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/27901
Pigweed-Auto-Submit: Wyatt Hepler <hepler@google.com>
Reviewed-by: Rob Mohr <mohrr@google.com>
Commit-Queue: Auto-Submit <auto-submit@pigweed.google.com.iam.gserviceaccount.com>