Gallery images scrroling bug sorted and video icon updated on related sto...

...ry cards

Jira tickets GIA-3052, GIA-3026
I used it to enforce the bottom media icon (play button/gallery/audio button in left bottom corner ) appearance in related story card to be the same as across the site (yellow circle with black triangle)  
ticket: https://jira.gutools.co.uk/browse/GIA-3026