Bump @open-wc/karma-esm from 2.13.27 to 2.13.28

Bumps [@open-wc/karma-esm](https://github.com/open-wc/open-wc/tree/HEAD/packages/karma-esm) from 2.13.27 to 2.13.28.
- [Release notes](https://github.com/open-wc/open-wc/releases)
- [Changelog](https://github.com/open-wc/open-wc/blob/master/packages/karma-esm/CHANGELOG.md)
- [Commits](https://github.com/open-wc/open-wc/commits/@open-wc/karma-esm@2.13.28/packages/karma-esm)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>