templates: search: Remove touchstart handler for loading overlay

The touchstart function loads the overlay which is at a higher z-index
than then element to be clicked. So the overlay loads but the element
(usually a filter item) beneath the overlay doesn't receive a "click"

Fixes: #1188

Author: michaelwood

grantnav/frontend/templates/search.html

@@ -169,7 +169,6 @@ <h1>Search input is not valid</h1>
   filters.forEach(function (filter) {
     // Add event listeners for click and touch events
     filter.addEventListener('click', show_overlay);
-    filter.addEventListener('touchstart', show_overlay);
 
     // Add event listener for keyboard events
     filter.addEventListener('keydown', function (event) {