UI Improvements to center channel (#2790)

Removing time from the center channel on sp (mobile)

Liking mention color to search highlight color aswell

Adjusting vertical spacing on mobile

Removing profile pic from mobile LHS header

Updating styles for the RHS

Fixing btn-danger

webapp/utils/utils.jsx

@@ -761,7 +761,7 @@ export function applyTheme(theme) {
     }
 
     if (theme.mentionHighlightLink) {
-        changeCss('.app__body .mention--highlight .mention-link', 'color:' + theme.mentionHighlightLink, 1);
+        changeCss('.app__body .mention--highlight .mention-link, .app__body .mention--highlight, .app__body .search-highlight', 'color:' + theme.mentionHighlightLink, 1);
     }
 
     if (!theme.codeTheme) {