Bump vega-functions and vega in /shell-ui

Bumps [vega-functions](https://github.com/vega/vega) and [vega](https://github.com/vega/vega). These dependencies needed to be updated together.

Updates `vega-functions` from 5.15.0 to 5.18.0
- [Release notes](https://github.com/vega/vega/releases)
- [Commits](vega/vega@v5.15.0...v5.18.0)

Updates `vega` from 5.30.0 to 5.33.0
- [Release notes](https://github.com/vega/vega/releases)
- [Commits](vega/vega@v5.30.0...v5.33.0)

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

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Author: dependabot[bot]