Bump @open-wc/karma-esm from 3.0.3 to 3.0.4 (#289)

Bumps [@open-wc/karma-esm](https://github.com/open-wc/open-wc/tree/HEAD/packages/karma-esm) from 3.0.3 to 3.0.4.
- [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@3.0.4/packages/karma-esm)

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