Warning: Failed to save: Failed to CreateCacheEntry: Received non-retryable error: Failed request: (409) Conflict: cache entry with the same key, version, and scope already exists

I'm seeing the following error e.g. [here](https://github.com/enola-dev/enola/actions/runs/14157243625/job/39658610815): `Warning: Failed to save: Failed to CreateCacheEntry: Received non-retryable error: Failed request: (409) Conflict: cache entry with the same key, version, and scope already exists`

I've noticed https://github.com/bazel-contrib/setup-bazel/issues/75#issuecomment-2736174996, which says (quote): _"There is currently an issue when multiple jobs attempt to upload the same cache, addressed in #71"_ however I don't think I had [another workflow running](https://github.com/enola-dev/enola/actions) which WROTE to the cache at that time (I may have had one running which tried to READ the cache, I'm not sure; but that hopefully shouldn't be related).

If #71 will definitely fix this - awesome! But I thought I'd let you know.

Start by reviewing the linked GitHub Actions workflow run and the cache-save failure, then compare the behavior with setup-bazel issue #71. Done means establishing whether another workflow or cache write caused the 409 conflict and documenting whether the referenced fix addresses this case.

Written by the indexing model from the issue text.