win32u: Use a color table with default palette for 8bpp window surfaces.
NtGdiCreateDIBSection will allocate a color table for 8bpp bitmap anyway and if biClrUsed isn't set, we will later fail any color lookup.
NtGdiCreateDIBSection will allocate a color table for 8bpp bitmap anyway and if biClrUsed isn't set, we will later fail any color lookup.