Fix incorrect gamma/contrast values when playing windowed

[iakoboss7]

Hello,

please fix the annoying weird gamma/contrast issue that NC soft never fixed, it makes whoever plays windowed have washed out colors on the rest of the screen.

the fix is very simple: https://l2classic.club/forum/topic/21217-l2-gamma-and-brightness-problem-fix/

i can edit the l2.ini for you if you need, sadly if you do not provide it yourself it doesnt pass anticheat....