Upload GCS release artifact (latest) fails deterministically on small files

The `Upload GCS release artifact (latest)` step in `cd.yml` may fail deterministically. In [my case](https://github.com/grafana/grafana-assistant-app/actions/runs/27253827766) it failed 3 consecutive attempts with the same error:

```
google-github-actions/upload-cloud-storage failed with: the offset is lower than the number of bytes written.
The server has 0 bytes and while 10 bytes has been uploaded - thus 10 bytes are missing.
Stopping as this could result in data loss. Initiate a new upload to continue.
```

The failing file is a 57-byte `.sha1` checksum uploaded with `resumable: true` and `gzip: true` (action defaults). The object is actually written to GCS successfully, but `upload-cloud-storage@v3.0.0` reports a failure (probably due to offset tracking on the resumable upload).

The upstream action has multiple reports of this: [#331](https://github.com/google-github-actions/upload-cloud-storage/issues/331), [#362](https://github.com/google-github-actions/upload-cloud-storage/issues/362), [#363](https://github.com/google-github-actions/upload-cloud-storage/issues/363), and an open request for retry logic at [#394](https://github.com/google-github-actions/upload-cloud-storage/issues/394).

Possible fixes:
- Set `resumable: false` for the latest upload (the files are small enough that resumable adds no value)