[FIX] website: GA key

`_` is not available when loading this part of the template, leading to
an error on `_.str.trim()`.

We can simply use `trim()` to do so. By the way, `google_analytics_key`
is now trimmed automatically when adding it in the settings, so this is
only useful for migrated databases.

Fixes #38891
opw-2089296

closes odoo/odoo#39255

Signed-off-by: Nicolas Martinelli (nim) <nim@odoo.com>

addons/website/views/website_templates.xml

@@ -294,7 +294,7 @@
             m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
             })(window,document,'script','//www.google-analytics.com/analytics.js','ga');
 
-            ga('create', _.str.trim('<t t-esc="website.google_analytics_key"/>'), 'auto');
+            ga('create', '<t t-esc="website.google_analytics_key"/>'.trim(), 'auto');
             ga('send','pageview');
         </script>
     </xpath>