BHV-12273: fix index of pages update rountine in VerticalDelegate.js

## Issue
Index of pages in DataList have a same value in certain case.

## Cause
refresh() function has a index setting routine according to pageCount value.
But they can not handle a condition like blew.

* refresh() function

(firstIndex > pageCount && secondIndex > pageCount)  ==> OK
(firstIndex > pageCount && secondIndex < pageCount)  ==> OK
(firstIndex < pageCount && secondIndex > pageCount)  ==> Not Good(result : firstIndex == secondIndex)
(firstIndex < pageCount && secondIndex < pageCount)  ==> OK

## Fix
Add one line which can handle those condition.
(* This fix is similar fix with https://github.com/enyojs/enyo/pull/818 - but his is for 2.5.1)

Enyo-DCO-1.1-Signed-off-by: Sungbae Cho sb.cho@lge.com