debugger: Fix removal of running sessions when spawning a debug session (#30384)

Fixed regression introduced in
https://github.com/zed-industries/zed/pull/29646/files#diff-85cbb0a26f1949431ec63870fc2d52b583227a5a00b6e10b64dcdb7fe7ef13afL314

Release Notes:

- N/A
79ba22673bPiotr Osiewicz committed on 5/9/2025, 10:52:43 PM· committed by GitHubparent074e783
1 file changedLine totals unavailable