fix PictureBox when width or height is null

src/BizHawk.Client.EmuHawk/tools/Lua/Libraries/FormsLuaLibrary.cs

@@ -415,10 +415,9 @@ namespace BizHawk.Client.EmuHawk
 			if (width.HasValue && height.HasValue)
 			{
 				pictureBox.LuaResize(width.Value, height.Value);
+				SetSize(pictureBox, width.Value, height.Value);
 			}
 
-			SetSize(pictureBox, width.Value, height.Value);
-
 			return (long)pictureBox.Handle;
 		}