pw_build_info: Add missing linker search directory in Bazel

For build_id library, so the snippet file can be found when Pigweed
is built as an external module.

The 'pw_linker_script' rule should be modified to better support the
inclusion of snippets to a linker script.

Change-Id: I880c10e2e3ed80498725946e3277ce3b30b4164b
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/241893
Reviewed-by: Aaron Green <aarongreen@google.com>
Commit-Queue: Auto-Submit <auto-submit@pigweed-service-accounts.iam.gserviceaccount.com>
Reviewed-by: Rob Mohr <mohrr@google.com>
Reviewed-by: Taylor Cramer <cramertj@google.com>
Pigweed-Auto-Submit: Armando Montanez <amontanez@google.com>
Reviewed-by: Wyatt Hepler <hepler@google.com>
Lint: Lint 🤖 <android-build-ayeaye@system.gserviceaccount.com>
Docs-Not-Needed: Armando Montanez <amontanez@google.com>
Reviewed-by: Armando Montanez <amontanez@google.com>