[volt] lets add read_cfg to MANGOHUD_CONFIG to always load the user config

Author: pythonlover02

src/gpu_launch.py

@@ -638,6 +638,7 @@ def _generate_frame_control_env_vars(frame_control_widgets):
                     mangohud_config_parts.append(mapped_value)
 
         if mangohud_config_parts:
+            mangohud_config_parts.insert(0, 'read_cfg')
             config_value = ','.join(mangohud_config_parts)
             env_vars.append(f'MANGOHUD_CONFIG={config_value}')