DolphinQt: Fix post processing shader selector when language is not English.

[rsgnz]

This fixes the check and prevents translations of the string "(off)" from being saved in GFX.ini

[BhaaLseN]

This feels a bit weird, the better solution would be storing a non-translated string in first place. Otherwise switching languages would break this as well (although it seems unlikely that someone starts in their native language then switches to English, or vice versa while a post processing shader is active).

[rsgnz]

The issue was introduced with the game-specific GFX settings #13063

What seems clear is that the value saved in GFX.ini when you don't want to use a post-processing shader, is an empty value. That was the case before those changes, and I think it was intended to keep it that way afterwards as well.

Switching languages ​​requires restarting Dolphin, so this is not something that affects the solution for the issue.

In the case of changing the language and having in GFX.ini one of the translations of the string "(off)", it will not be found in the shader list, and the value will become empty.

[JosJuice]

What seems clear is that the value saved in GFX.ini when you don't want to use a post-processing shader, is an empty value. That was the case before those changes, and I think it was intended to keep it that way afterwards as well.

Yes, I agree with that. But it's strange that Config::GFX_ENHANCE_POST_SHADER ends up getting set to a translated string to begin with. It feels like the problem is being addressed in the wrong place.