copilot: Fix config dir logic to support Flatpak environments (#32901)

Closes #30784

In github copilot we were not handling the config path correctly for
FLATPAK.

* Only tested on mac don't have access to other platform. But this
should work on other platform as well. It follows the similar pattern
seen in zed config path resolution.
- [x] Macos
- [ ] Linux
- [ ] Linux with Flatpak
- [ ] Windows

Release Notes:

- Fix copilot config detection for flatpack
e914d84f00Umesh Yadav committed on 6/19/2025, 2:32:02 PM· committed by GitHubparentec0f2fa
3 files changedLine totals unavailable