build(deps): bump shell-quote and @edx/frontend-build

Bumps [shell-quote](https://github.com/substack/node-shell-quote) and [@edx/frontend-build](https://github.com/edx/frontend-build). These dependencies needed to be updated together.

Updates `shell-quote` from 1.7.2 to 1.7.3
- [Release notes](https://github.com/substack/node-shell-quote/releases)
- [Changelog](https://github.com/substack/node-shell-quote/blob/master/CHANGELOG.md)
- [Commits](https://github.com/substack/node-shell-quote/compare/v1.7.2...1.7.3)

Updates `@edx/frontend-build` from 6.1.1 to 12.0.3
- [Release notes](https://github.com/edx/frontend-build/releases)
- [Commits](openedx/frontend-build@v6.1.1...v12.0.3)

---
updated-dependencies:
- dependency-name: shell-quote
  dependency-type: indirect
- dependency-name: "@edx/frontend-build"
  dependency-type: direct:production
...

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Author: dependabot[bot]