Telemetry: Clean up tap and click_element gestures.

tools/perf/page_sets/pica.json

 {
   "description": "Pica demo app for the Polymer UI toolkit",
   "archive_data_file": "data/pica.json",
   "pages": [
     { "url": "http://localhost/polymer/projects/pica/",
       "script_to_evaluate_on_commit":
           "document.addEventListener('WebComponentsReady', function(){var unused = document.body.offsetHeight; window.__pica_load_time = performance.now(); setTimeout(function(){window.__web_components_ready=true}, 1000)})",
       "navigate_steps" : [
         { "action": "navigate" },
         { "action": "wait", "javascript": "window.__web_components_ready" }
-      ],
-      "smoothness": {
-        "action": "tap_element",
-        "find_element_expression": "document.querySelector('pi-app').$.Topics.$.topics.$.container.querySelector('.item > .card')",
-        "wait_for_event": "polymer-pages-animation-end"
-      }
+      ]
     }
   ]
 }