[bazel] Allow 'sbase_binaries' to be used by Bazel build rules This allows Bazel build rules to get the same list of sbase binaries as is used by GN. Bug: 505830390 Change-Id: I1548d74863e2011edb168b4ecc5a7610de5ff5b2 Reviewed-on: https://fuchsia-review.googlesource.com/c/third_party/sbase/+/1586928 Commit-Queue: Aaron Wood <aaronwood@google.com> Fuchsia-Auto-Submit: Aaron Wood <aaronwood@google.com> Reviewed-by: David Fang <fangism@google.com>