Github Actions error unless run-tests.yaml is changed

[Something goes wrong](https://github.com/deepgenomics/GenomeKit/actions/runs/19633122461/job/56219086162) on run-tests.yaml step `restore_mamba_cache` unless run-tests.yaml itself is changed:
> Error: The template is not valid. .github/workflows/run-tests.yaml (Line: 53, Col: 16): hashFiles('.github/workflows/run-tests.yaml, .github/actions/**') failed. Fail to hash files under directory '/Users/runner/work/GenomeKit/GenomeKit'

Might be a problem with the working dir (GenomeKit is doubled in the error message). This is difficult to debug because any change to the workflow file causes the issue to go away.

The cache in question is saved in actions/build-gk `save_mamba_cache`.