Fix gcloud set up in load-metrics.yml

[e-belfer]

Overview

What problem does this address?
I'm not 100% sure what caused the issue, but the load_metrics.yml was suddenly having a problem authenticating gcloud (see, e.g. https://github.com/catalyst-cooperative/pudl-usage-metrics/actions/runs/11292667735).

What did you change in this PR?
Added a gcloud set up step mirroring the one used in save_daily_metrics.yml, and specified the shell running the gcloud command.

Testing

How did you make sure this worked? How can a reviewer verify this?
See https://github.com/catalyst-cooperative/pudl-usage-metrics/actions/runs/11292842735.

To-do list

Tasks

Beta Give feedback

1. Review the PR yourself and call out any questions or issues you have

[jdangerx]

Looks good to me! Small suggestion to add a little context around the strange bash -l {0} if possible, but totally fine to merge as is as well.

[jdangerx]

This was necessary for this step but not the later IP-clearing step? Weird... if you have any context on what was going on that necessitated this it might be nice to include as a comment.