Bump phoenix_live_dashboard from 0.8.2 to 0.8.4

Bumps [phoenix_live_dashboard](https://github.com/phoenixframework/phoenix_live_dashboard) from 0.8.2 to 0.8.4.
- [Release notes](https://github.com/phoenixframework/phoenix_live_dashboard/releases)
- [Changelog](https://github.com/phoenixframework/phoenix_live_dashboard/blob/main/CHANGELOG.md)
- [Commits](phoenixframework/phoenix_live_dashboard@v0.8.2...v0.8.4)

---
updated-dependencies:
- dependency-name: phoenix_live_dashboard
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>