prevent default in places sample (#341)

Co-authored-by: William French <[email protected]>

Author: oppenheimera

samples/3d-places/index.ts

@@ -20,6 +20,7 @@ async function init() {
     document.body.append(map3DElement);
 
     map3DElement.addEventListener('gmp-click', async (event) => {
+        event.preventDefault();
         if (event.placeId) {
             const place = await event.fetchPlace();
             await place.fetchFields({ fields: ['*'] });