Fix GCP auth step for GitHub Actions workflows

[Amar3tto]

Addresses #30760, #33065, #32161.

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[damccorm]

Thanks

[Amar3tto]

@damccorm This PR eliminates errors in Auth step, but still not working because of Invalid JWT Signature.
Could you please refresh JSON key and update GCP_SA_KEY secret?

[damccorm]

@damccorm This PR eliminates errors in Auth step, but still not working because of Invalid JWT Signature. Could you please refresh JSON key and update GCP_SA_KEY secret?

We can try that. In the meantime, I think we should revert this since it went from sometimes failing to always failing - https://github.com/apache/beam/actions/runs/14446457300/job/40508116220

Revert PR - #34626

[damccorm]

@damccorm This PR eliminates errors in Auth step, but still not working because of Invalid JWT Signature. Could you please refresh JSON key and update GCP_SA_KEY secret?

We can try that. In the meantime, I think we should revert this since it went from sometimes failing to always failing - https://github.com/apache/beam/actions/runs/14446457300/job/40508116220

Revert PR - #34626

Actually, I checked and the JSON key currently in use is still valid. So I do not think that is the problem