feat(vitest): add run summary in GitHub Actions Reporter

[macarie]

Description

Resolves #9498

Spent some time on this today, not completely sure about the format yet.

Summary Preview

Open Questions:

• What title should we use? Vitest Summary is just a placeholder
• Is the 🔴 High priority label useful? Nope
• Should we display the run stats? What about errors?
• Should tasks be sorted by retryCount?

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Tests

• Run the tests with pnpm test:ci.

Documentation

• If you introduce new functionality, document it. You can run documentation with pnpm run docs command.

Changesets

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