xtask: Fix `setup-webrtc` config overwrite refusal and Windows path format (#57058)

Self-Review Checklist:

- [x] I've reviewed my own diff for quality, security, and reliability
- [x] No unsafe blocks
- [x] The content is consistent with the [UI/UX
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
- [x] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable

Closes #57057

Release Notes:

- N/A

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Co-authored-by: zed-zippy[bot] <234243425+zed-zippy[bot]@users.noreply.github.com>
9abb73ee32Gepcel committed on 5/18/2026, 10:32:04 PM· committed by GitHubparent2a00db0
1 file changedLine totals unavailable