Fix listing of enabled features in rerun --version

[emilk]

What

RERUN_IS_PUBLISHING was incorrectly set when we weren't publishing crates.
This lead to a rerun --version not showing the correct feature flags in our release.
This should fix it.
I'll make an alpha-release once merged to verify.

Checklist

• I have read and agree to Contributor Guide and the Code of Conduct
• I've included a screenshot or gif (if applicable)
• I have tested the web demo (if applicable):
  • Using examples from latest main build: rerun.io/viewer
  • Using full set of examples from nightly build: rerun.io/viewer
• The PR title and labels are set such as to maximize their usefulness for the next release's CHANGELOG
• If applicable, add a new check to the release checklist!
• If have noted any breaking changes to the log API in CHANGELOG.md and the migration guide

• PR Build Summary
• Recent benchmark results
• Wasm size tracking

To run all checks from main, comment on the PR with @rerun-bot full-check.

[github-actions]

Latest documentation preview deployed successfully.

Result	Commit	Link
✅	03aaaeb	https://landing-5795gga9z-rerun.vercel.app/docs

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