Cannot drag and drop a session from a custom group back to its workspace group

[ulugbekna]

repro:

1. move a session to a custom group
2. try to drag and drop the session back to its workspace group - 🐛 doens't work

Version: 1.137.0-insider (Universal)
Commit: 1f625ad
Date: 2026-09-02T04:27:24Z
Electron: 42.10.0
ElectronBuildId: 15109253
Chromium: 148.0.7778.280
Node.js: 24.18.1
V8: 14.8.178.38-electron.0
@github/copilot: 1.0.83-0
@github/copilot-sdk: 1.0.13-preview.4
OS: Darwin arm64 25.6.0