feat: adds tune LLM sample

[telpirion]

This PR adds the region tag aiplatform_model_tuning for Node.js.

[snippet-bot]

Here is the summary of changes.

You are about to add 1 region tag.

• ai-platform/snippets/tuning.js:28, tag aiplatform_model_tuning

---

This comment is generated by snippet-bot.
If you find problems with this result, please file an issue at:
https://github.com/googleapis/repo-automation-bots/issues.
To update this comment, add snippet-bot:force-run label or use the checkbox below:

• Refresh this comment

[pattishin]

@telpirion nice! do you mind checking on the ai-platform-snippets workflow failure?

[kweinmeister]

Looks like it might just be missing "sinon" in devDependencies.

[kweinmeister]

In logs, failing with:

Tune a model
       should prompt-tune an existing model:
     Error: 3 INVALID_ARGUMENT: You do not have permission to act as service_account:

FYI @gericdong

[telpirion]

For posterity: the GCP project used for Vertex AI (pointed to by process.env.CAIP_PROJECT_ID) is not the same as the project used by the rest/most of nodejs-docs-samples. When this test attempted to create a new storage bucket for output, it was using invalid ADC (not using the process.env.CAIP_PROJECT_ID service account).

[pattishin]

Checking this out more. Investigating that last test failure around the uCAIP service account 🧐

[gericdong]

Just removed the public access prevention for the storage bucket to see if this is the cause of the permission issue.

[gericdong]

The CI test was aborted because the featurestore test timed out the test run, as message shown below. The CI will be rerun once the featurestore test is stable.

AI platform create featurestore with fixed nodes
Error: The operation was canceled.

[telpirion]

If the Featurestore tests are a known source of flaky test, we might want to set them to ignore/skip.

[gericdong]

Agree. Another repo is also temporarily skipping featurestore tests.