chore: Remove unused (and deprecated) Google Analytics

This removes Google Analytics, which was introduced in 76c1537

> For a while we also had GA and we used that more I think. Not sure
> what happened to it (e.g. we never migrated to GA4 AFAIK), we don’t
> look at website analytics that much.

Author: mroderick

app/assets/javascripts/analytics.js

@@ -22,7 +22,6 @@
 //= require pickadate/picker
 //= require pickadate/picker.date
 //= require pickadate/picker.time
-//= require analytics
 //= require gosquared
 //= require subscriptions-toggle
 //= require invitations