Fix sorting issue

TNL-952
the sub problems in an vertical have ids which is combination of vertical id along with sub-problem position (in which they added) , an example is 

data_list = 'abc_1', 'abc_2', 'abc_11' ,'abc_3'

The problem rises due to sorting of strings with numbers .Most sorting algorithms compare ASCII values, which produces an ordering that is inconsistent with human logic.

after sorting
sorted_list = 'abc_1', 'abc_11', 'abc_2','abc_3'

so the fix is to sort the responses on the basis of position no which is at last place in id and then convert to numbers so the sorting will be base on integers instead of strings