Fixed Windows scRGB screenshots + Game Brightness

[XgarhontX]

On Windows, scRGB screenshots were incorrectly affected by Game Brightness when != 80.
(WearyOlly confirmed it's not on Linux.)
TODO: rgba16unorm

Fix:

// RGBA16F.
for (int c = 0; c < 4; c++) {
    bits = mappedView.data().getShort(basePos + c * 2);
    datas[c] = Float.float16ToFloat(bits);
    if (System.getProperty("os.name").startsWith("Windows")) datas[c] *= 80.f / config.customGamePaperWhiteBrightness; //Fixes Game Brightness scaling for Windows.
}

[rrtt217]

Omg I forgot to do that, but the condition you uses is technologically incorrect

[rrtt217]

RGBA16UNORM is only functional on PQ transfer function, and for Rec.2100 PQ no transformation is actually needed, wysiwyg.