Scroll box hand icon is small when DPI scaling is enabled

The scroll box widget currently hides the cursor and manually draws a closed hand software cursor in SScrollBox::OnPaint when right clicking and dragging. This software cursor does not account for DPI scaling, and will appear smaller than the default cursor as a result.

const FSlateBrush* Brush = FCoreStyle::Get().GetBrush(TEXT("SoftwareCursor_Grab"));
FSlateDrawElement::MakeBox(
    OutDrawElements,
    ++NewLayerId,
    AllottedGeometry.ToPaintGeometry( SoftwareCursorPosition - ( Brush->ImageSize / 2 ), Brush->ImageSize ),
    Brush
); 

1. Create a scroll box and fill it with text
2. Right click the body of the scroll box and drag
3. Note that the closed hand icon is smaller than the default cursor