chore(deps): bump libphonenumber-js in /build/frontend-legacy

Bumps [libphonenumber-js](https://gitlab.com/catamphetamine/libphonenumber-js) from 1.12.42 to 1.13.7.
- [Changelog](https://gitlab.com/catamphetamine/libphonenumber-js/blob/master/CHANGELOG.md)
- [Commits](https://gitlab.com/catamphetamine/libphonenumber-js/commits/master)

---
updated-dependencies:
- dependency-name: libphonenumber-js
  dependency-version: 1.13.7
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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Author: dependabot[bot]