Bump vega-selections from 5.4.1 to 5.5.0 in /ui-tests (#7592)

Bumps [vega-selections](https://github.com/vega/vega) from 5.4.1 to 5.5.0.
- [Release notes](https://github.com/vega/vega/releases)
- [Commits](vega/vega@v5.4.1...v5.5.0)

---
updated-dependencies:
- dependency-name: vega-selections
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>