[IMP] website_event: improve web tracking

In 2 ways:
- by ignoring prefetched pages: indeed some page were reported inaccurately
as being viewed by the user when they were only prefetched.
- by adding the page /event in the tracked page as the page is obviously
important in the event business

Technical notes:
- The prefetched pages are ignored thanks to an header X-Disable-Tracking added
on each prefetch request in the service worker.
- Adding the page /event as a tracked page has increased the number of queries
when browsing the page /event. That's why some query count have been updated in
TestOnlineEventPerformance.

Task-2476513

Part-of: odoo/odoo#86031

addons/test_event_full/tests/test_performance.py

@@ -444,7 +444,7 @@ class TestOnlineEventPerformance(EventPerformanceCase, UtilPerf):
         # website customer data
         with freeze_time(self.reference_now):
             self.authenticate('user_eventmanager', 'user_eventmanager')
-            with self.assertQueryCount(default=50):  # tef only: 49
+            with self.assertQueryCount(default=60):  # com runbot: 59 - ent runbot:60
                 self._test_url_open('/event')
 
     @warmup
@@ -452,7 +452,7 @@ class TestOnlineEventPerformance(EventPerformanceCase, UtilPerf):
         # website customer data
         with freeze_time(self.reference_now):
             self.authenticate(None, None)
-            with self.assertQueryCount(default=30):
+            with self.assertQueryCount(default=39):  # com runbot: 39 - ent runbot: 39
                 self._test_url_open('/event')
 
     # @warmup

addons/website_event/views/event_templates_list.xml

@@ -2,7 +2,7 @@
 <odoo>
 
 <!-- Index -->
-<template id="index" name="Events">
+<template id="index" name="Events" track="1">
     <t t-call="website.layout">
         <div id="wrap" class="o_wevent_index">
             <!-- Options -->

addons/website_event_track/static/src/js/service_worker.js

@@ -236,14 +236,20 @@ const matchCache = async (request) => {
 
 /**
  *
- * @param {FetchEvent} param0
+ * @param {Request} request
+ * @param {object} [options]
+ * @param {Boolean} [options.disableTracking] whether adding a header preventing the server to track the request
  * @returns {Promise<Response>}
  */
-const processFetchRequest = async ({ request }) => {
+const processFetchRequest = async (request, options) => {
     const requestCopy = request.clone();
     let response;
     try {
-        response = await fetch(request);
+        if (options && options.disableTracking) {
+            response = await fetch(request, { headers: { 'X-Disable-Tracking': '1' } });
+        } else {
+            response = await fetch(request);
+        }
         await cacheRequest(request, response);
     } catch (requestError) {
         if (isCachableRequest(requestCopy)) {
@@ -308,7 +314,7 @@ const prefetchUrls = async (urls = []) => {
             continue;
         }
         try {
-            await processFetchRequest({ request: new Request(url) });
+            await processFetchRequest(new Request(url), { disableTracking: true });
         } catch (error) {
             console.error(`fail to prefetch ${url} : ${error}`);
         }
@@ -347,7 +353,7 @@ const processMessage = (data) => {
 };
 
 self.addEventListener("fetch", (event) => {
-    event.respondWith(processFetchRequest(event));
+    event.respondWith(processFetchRequest(event.request));
 });
 
 self.addEventListener("sync", (event) => {