ENYO-2790: Accessibility: The slider value does not change while no popup.
ENYO-2790: Accessibility: The slider value does not change while no popup.

Issue
The slider value does not change while no popup.

Cause
After the popup property is changed from true to false, both
'aria-valuetext' and 'aria-valuenow' are exist.
Web engine reads only 'aria-valuetext' if two of them are in a dom node.

Fix
Before setting 'aria-valuetext' or 'aria-valuenow', set them to null.

Apply this fix on ProgressBar as well

https://jira2.lgsvl.com/browse/ENYO-2790
Enyo-DCO-1.1-Signed-off-by: Jaewon Jang jaewon98.jang@lgepartner.com

enyojs/moonstone