round-off weight value while returing grading policy

TNL-884
@waheedahmed @mlkwaqas @adampalay 
Fix issue where when a user tries to set weight to some specific value e.g, '29' then 'jsonize_grader' method returns it as floating point '28.999999999999996' and displaying it on front end gives '28' instead of '29'
Honestly, I don't understand how this fixes the issue (why parseInt, which did appear to fix some issues, did not fix this one).