chore(deps): bump @tensorflow/tfjs from 4.13.0 to 4.15.0

Bumps [@tensorflow/tfjs](https://github.com/tensorflow/tfjs) from 4.13.0 to 4.15.0.
- [Release notes](https://github.com/tensorflow/tfjs/releases)
- [Changelog](https://github.com/tensorflow/tfjs/blob/master/cloudbuild-release.yml)
- [Commits](tensorflow/tfjs@tfjs-v4.13.0...tfjs-v4.15.0)

---
updated-dependencies:
- dependency-name: "@tensorflow/tfjs"
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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