Investigate Redundant `@com_google_benchmark//:benchmark` Dependency in Bazel Builds

Pull request #15543 fixed build failures in several benchmark targets on the macOS Bazel CI. The builds were failing because they were missing a direct dependency on `@com_google_benchmark//:benchmark`, even though they already depended on `@com_google_benchmark//:benchmark_main`.

While adding the explicit dependency resolves the build errors, it's not clear why this is necessary. According to the `google/benchmark` [BUILD.bazel file](https://github.com/google/benchmark/blob/d65c35c406858939084ef96c72663ec382f75d37/BUILD.bazel#L95), the `:benchmark_main` target depends on `:benchmark` and should export the necessary headers and symbols.

This issue affects the macOS Bazel CI builds.

This issue is to track the investigation into the root cause of this behavior:

1. Why is a direct dependency on `@com_google_benchmark//:benchmark` required when a dependency on `@com_google_benchmark//:benchmark_main` already exists?
2. Why does this issue appear to be specific to the macOS Bazel CI build environment?
3. Is there a more fundamental issue in how dependencies are being resolved or in the toolchain configuration?

**Acceptance Criteria:**

* Understand and document the reason for the seemingly redundant dependency.
* Determine if a configuration change can remove the need for the explicit dependency on `@com_google_benchmark//:benchmark` in the benchmark targets.

**Reference:**

* PR #15543: fix(bazel): Add missing dependency to benchmark targets

Start with PR #15543 and the affected benchmark targets in the macOS Bazel CI builds. Compare their dependency declarations with google/benchmark's referenced BUILD.bazel file and investigate how the macOS toolchain resolves benchmark and benchmark_main. Done means documenting the cause and determining whether a configuration change can remove the explicit dependency.

Written by the indexing model from the issue text.