Update GOverlay to 0.3.7
- Finally implemented loading saved files in mangohud and vkbasalt
- Default settings for FPS limit and VSYNC changed to "unset"
- Removed debrand option in vkbasalt since it's deprecated on the original project
Test Plan: Checked saving and loading settings, tested both supported overlays.
Reviewers: Triage Team, JoshStrobl
Reviewed By: Triage Team, JoshStrobl
Differential Revision: https://dev.getsol.us/D9364