Bump vega from 5.20.2 to 5.23.0 in /ui-tests (#1297)

Bumps [vega](https://github.com/vega/vega) from 5.20.2 to 5.23.0.
- [Release notes](https://github.com/vega/vega/releases)
- [Commits](vega/vega@v5.20.2...v5.23.0)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Duc Trung Le <[email protected]>

Author: dependabot[bot]