BHV-731: Fix issue with "Scroll To Index" in moon.DataList sample.

Issue
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If the "Scroll To Index" `ExpandableInput` is used to navigate to a specific index, and then scrolling is performed, using "Scroll To Index" will not navigate to the originally navigated index unless the index is changed in the input.

Fix
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Handle the `onblur` instead of the `onchange` event and detect if scrolling has occurred.

Enyo-DCO-1.1-Signed-off-by: Aaron Tam <aaron.tam@lge.com>