SOC-3469| Show all comment on stream what has UILinkActivity threw excep...

...tion as screenshot.

Fix description: 
* Problem: 
** When comment on link activitiy, if the number of comment > 12, show error if user clicks to show all comments.
** Missing of declare 1 variable in template file (UILinkActivity.gtmpl): In case show the hidden comments, will be called to undeclare variable => Exception.
* How to fix: Don't need to use this variable. Set <%=uicomponent.event("SetCommentListStatus", "all")%> to show all comment in case have hidden comments.