Mobile Web: Auto-focus cursor in the search box (#5284)

* Mobile Web: Auto-focus cursor in the search box and open keyboard when the search icon is tapped

* fixed issue with safari mobile view

* added isFocus props to search_bar.jsx component

* used 'x' and fixed spacing

* changed 'x' icon and fixed css

* added aria-hidden='true'

webapp/sass/components/_search.scss

@@ -51,7 +51,7 @@
     top: 15px;
 }
 
-.sidebar__clear-icon {
+.sidebar__search-clear {
     @include opacity(.5);
     color: $dark-gray;
     width: 40px;