Properly process files that cannot be open for a reason (#37170)

Follow-up of https://github.com/zed-industries/zed/pull/36764

* Fix `anyhow!({e})` conversion lossing Collab error codes context when
opening a buffer remotely

* Use this context to only allow opening files that had not specific
Collab error code

Release Notes:

- N/A
5001c03711Kirill Bulatov committed on 8/29/2025, 2:14:27 PM· committed by GitHubparent20d32d1
4 files changedLine totals unavailable