Fixes for MSI GE76 Raider 11UH: GTK warnings, UI freeze, and CPU 0 temp

[tagos777]

Hi! I've fixed several issues while running OpenFreezeCenter on my MSI GE76 Raider 11UH (Linux).

What was fixed:

1. Resolved GTK "widget already inside a container" warnings by removing redundant fixed.add() calls.
2. Fixed system freezes by increasing EC polling interval to 1000ms.
3. Corrected EC addresses for GE76 Raider 11UH (CPU temperature was 0).
4. Improved config_writer to be more robust.

I've attached my corrected OFC.py and config.py files. Hope this helps other users!

config.py
OFC.py