chore(deps): bump @nextcloud/vue in /build/frontend-legacy

Bumps [@nextcloud/vue](https://github.com/nextcloud-libraries/nextcloud-vue) from 8.38.0 to 8.39.0.
- [Release notes](https://github.com/nextcloud-libraries/nextcloud-vue/releases)
- [Changelog](https://github.com/nextcloud-libraries/nextcloud-vue/blob/v8.39.0/CHANGELOG.md)
- [Commits](nextcloud-libraries/nextcloud-vue@v8.38.0...v8.39.0)

---
updated-dependencies:
- dependency-name: "@nextcloud/vue"
  dependency-version: 8.39.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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Author: dependabot[bot]