Flamingo Theme preview is broken (on view mode) when "lessCode" is filled

1. Create a new flamingo theme
2. On the "advanced" category, put in the "lessCode" field the following code:

   @base: #f938ab;
   
   #mainContentArea .xcontent {
     color: saturate(@base, 5%);
     border-color: lighten(@base, 30%);
   }
   

3. Save the theme
   Now, in the preview of the view mode, you see the following error:

   ParseError: Unrecognised input
   in style.less.vm?colorTheme=no on line 143, column 1:
       @lessCode: @base: #f938ab;    #mainContentArea .xcontent {    color: saturate(@base, 5%);    border-color: lighten(@base, 30%);  };
   

There is a bug there because the preview is not supposed to handle the "lessCode" field.