Fix pane deduplication for unsaved buffers that have no path (#30834)

For example, running `zed some-new-path` multiple times would open
multiple tabs.

Release Notes:

- N/A

Co-authored-by: Max <max@zed.dev>
784d51c40fMichael Sloan committed on 5/18/2025, 2:22:06 PM· committed by GitHubparent0079c99
2 files changedLine totals unavailable