Remove scrolling attribute from embed iframe snippet
Remove scrolling attribute from embed iframe snippet

`scrolling` attribute is deprecated. Paged entries do not need it
since they hide scroll bars via `overflow: hidden`. For Scrolled
entries it needs to be removed to enable native scrolling.

REDMINE-19063

tf/pageflow,codevise/pageflow,tf/pageflow,codevise/pageflow,tf/pageflow,codevise/pageflow,codevise/pageflow,tf/pageflow