Merge branch 'support-string-piwik-website-ids' into 'master'

Supports Matomo/Piwik string website ID ("Protect Track ID" plugin)

Closes #61606

See merge request gitlab-org/gitlab-ce!28214

app/views/layouts/_piwik.html.haml

@@ -7,7 +7,7 @@
   (function() {
     var u="//#{extra_config.piwik_url}/";
     _paq.push(['setTrackerUrl', u+'piwik.php']);
-    _paq.push(['setSiteId', #{extra_config.piwik_site_id}]);
+    _paq.push(['setSiteId', "#{extra_config.piwik_site_id}"]);
     var d=document, g=d.createElement('script'), s=d.getElementsByTagName('script')[0];
     g.type='text/javascript'; g.async=true; g.defer=true; g.src=u+'piwik.js'; s.parentNode.insertBefore(g,s);
   })();