[Bug]: GitHub Reporter with the Dot reporter causing the GitHub annotations to print inline

[UndefinedOffset]

Version

1.60.0

Steps to reproduce

Run a test series on GitHub Actions with the github reporter and dots reporter (which should be the default with the CI env var being set) using 1.60.0 with at least one failing test.

Repo: https://github.com/webbuilders-group/electron-playwright-41272
Sample Action Run: https://github.com/webbuilders-group/electron-playwright-41272/actions/runs/27433593179/job/81089819792

Expected behavior

GitHub annotations should not appear in the step output but should appear on the annotations section the test run.

Actual behavior

GitHub annotations for the failures that were previously hidden in the output are now visible. The annotations also do not actually appear in the GitHub UI, so it seems GitHub is completely not detecting them.

Additional context

Appears to be a regression caused by #40590

Environment

System:
    GitHub actions using ubuntu-latest image

[mturac]

I can take this if the maintainers are open to a community PR. I reproduced the reporter interaction locally: with reporter: "dot,github", the dot reporter writes the failing-test marker without a trailing newline, then the GitHub reporter emits the ::error workflow command on the same line, so GitHub Actions no longer parses it as an annotation.

I have a narrow patch that starts per-test GitHub failure annotations on a fresh line and adds a regression in tests/playwright-test/reporter-github.spec.ts for the dot+github reporter combination.

Local validation on the patch:

npm run ttest -- reporter-github.spec.ts
npx eslint packages/playwright/src/reporters/github.ts tests/playwright-test/reporter-github.spec.ts
npm run tsc -- --pretty false
npm run build
git diff --check

Happy to open the PR if this issue is approved for external contribution.