This commit adds three new feed experiment goals:
* user publishes four posts within a week
* user reacts with a "heart", "unicorn", or "reading list" to an article
* user reacts with a "heart", "unicorn", or "reading list" to an article
four times in a week
In addition it adds it to the existing experiment. Adding it to the
existing experiment is acceptable because:
1. We can ignore the results
2. The experiments are structured such that these new goals could be met
with prior data.
3. Both variants are playing by the same rules, so the results relative
to each other are valid.
**There is a nuanced assumption in how we handle reactions:**
This implementation does not count by unique article reactions. However,
most folks will ❤️ , 🦄 , and 🔖 in one swoop; thus
those 3 reactions are all grouped into happening on one day.
Further, it's a reflection of the person taking an action after reading
a post, not how much action on that particular post.
**Rollback considerations:**
This also includes a feature flag that we can explicitly disable if we
overload the application with workers handling reaction goals. Using
`FeatureFlag.accessible?(:field_test_event_for_reactions)` returns
`true` unless we explicitly disable this flag.
Closesforem/forem#17669
8a4e1ebeba