test(ai): Remove flaky token count integration expect directives

[DellaBitta]

Discussion

We had some "ballpark" checks for the number of tokens returned in responses.

However, the number of tokens returned had a high variance based on general AI chaos and the model that was used. This PR replaces somewhat exacting token count checks with simple non-zero checks in order to reduce flake.

Additionally, the change removes toolUsePromptTokenCount checks for the gemini-2.0-flash model, which doesn't support this field.

Testing

This change updates the tests themselves. Tested locally.

API Changes

N/A.

[changeset-bot]

⚠️ No Changeset found

Latest commit: 686c3e2

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[google-oss-bot]

Size Report ¹

Affected Products

No changes between base commit (e6415dd) and merge commit (0f50db2).

Test Logs

• Base (e6415dd): https://github.com/firebase/firebase-js-sdk/actions/runs/19681774257
• Merge (0f50db2): https://github.com/firebase/firebase-js-sdk/actions/runs/19835434373

1. https://storage.googleapis.com/firebase-sdk-metric-reports/Z4035gV8km.html

[google-oss-bot]

Size Analysis Report ¹

Affected Products

No changes between base commit (e6415dd) and merge commit (0f50db2).

Test Logs

• Base (e6415dd): https://github.com/firebase/firebase-js-sdk/actions/runs/19681774257
• Merge (0f50db2): https://github.com/firebase/firebase-js-sdk/actions/runs/19835434373

1. https://storage.googleapis.com/firebase-sdk-metric-reports/aVmZGXjlIv.html