chore: Migrate gsutil usage to gcloud storage (#886)

Automated: Change comment references from `gsutil` to `gcloud storage`

This CL is part of the on going effort to migrate from the legacy
`gsutil` tool to the new and improved `gcloud storage` command-line
interface.
`gcloud storage` is the recommended and modern tool for interacting with
Google Cloud Storage, offering better performance, unified
authentication, and a more consistent command structure with other
`gcloud` components. 🚀

### Automation Details

This change was **generated automatically** by an agent that targets
users of `gsutil`.
The transformations applied are based on the [gsutil to gcloud storage
migration guide](http://go/gsutil-gcloud-storage-migration-guide).

### ⚠️ Action Required: Please Review and Test Carefully

While we have based the automation on the migration guide, every use
case is unique.
**It is crucial that you thoroughly test these changes in environments
appropriate to your use-case before merging.**
Be aware of potential differences between `gsutil` and `gcloud storage`
that could impact your workflows.
For instance, the structure of command output may have changed,
requiring updates to any scripts that parse it. Similarly, command
behavior can differ subtly; the `gcloud storage rsync` command has a
different file deletion logic than `gsutil rsync`, which could lead to
unintended file deletions.

Our migration guides can help guide you through a list of mappings and
some notable differences between the two tools.

Standard presubmit tests are run as part of this CL's workflow. **If you
need to target an additional test workflow or require assistance with
testing, please let us know.**

Please verify that all your Cloud Storage operations continue to work as
expected to avoid any potential disruptions in production.

### Support and Collaboration

The `GCS CLI` team is here to help! If you encounter any issues, have a
complex use case that this automated change doesn't cover, or face any
other blockers, please don't hesitate to reach out.
We are happy to work with you to test and adjust these changes as
needed.

**Contact:** `gcs-cli-hyd@google.com`

We appreciate your partnership in this important migration effort!

#gsutil-migration

Author: gurusai-voleti

.kokoro/trampoline_v2.sh

@@ -26,8 +26,8 @@
 # To run this script, first download few files from gcs to /dev/shm.
 # (/dev/shm is passed into the container as KOKORO_GFILE_DIR).
 #
-# gsutil cp gs://cloud-devrel-kokoro-resources/python-docs-samples/secrets_viewer_service_account.json /dev/shm
-# gsutil cp gs://cloud-devrel-kokoro-resources/python-docs-samples/automl_secrets.txt /dev/shm
+# gcloud storage cp gs://cloud-devrel-kokoro-resources/python-docs-samples/secrets_viewer_service_account.json /dev/shm
+# gcloud storage cp gs://cloud-devrel-kokoro-resources/python-docs-samples/automl_secrets.txt /dev/shm
 #
 # Then run the script.
 # .kokoro/trampoline_v2.sh