wingdi: request BGRA for 32 bits display

In 32 bits we don't use the mask in the DC (BI_RGB [1]) so we don't need to rely on a matching mask on input either.

The alpha byte of each pixel will be ignored.

It is more efficient and safe from a mask manipulation.

[1] https://learn.microsoft.com/en-us/windows/win32/api/wingdi/ns-wingdi-bitmapinfoheader

Fixes bogus colors after 081a0e62.