Fix title conversions

[dphiffer]

The status quo is that title tests are all messed—when they're configured to only convert on "homepage click" they are still getting conversion numbers added on pageload. This PR fixes the problem and cleans up some of the structures that made it hard to see the problem in the first place.

[BatMiles]

these var names are so much clearer

[BatMiles]

Trying to test locally (mostly for my own familiarity with the plugin) - when you say 'configured to only convert on 'homepage click'', does that mean the 'Conversion Criterion' is 'Click', with the target selector/content set to the article's title link on the homepage?

[dphiffer]

Yeah exactly. You should be able to test this either from the plugin's docker setup, or from the website's. I think the latter is better from a "getting familiarized" standpoint. I'd pull down the most recent changes that add data-id to the homepage, and then:

cd wp/wp-content/plugins
rm -rf split-tests
git clone [email protected]:the-markup/split-tests.git
cd split-tests
git checkout fix-title-conversions
npm install
npm run build

And then just make sure the plugin is activated (via wp/conf/wp-config-local.php and wp/wp-content/mu-plugins/active-plugins.php).

Making the post title test would look like this:

1. Pick an article to test, go to its editor
2. Scroll down and add a title variant (save)
3. Go to Split Tests and edit the associated split test (it gets created automatically)
4. Edit so that it only runs on the homepage
5. Change the conversion criterion to be "click" and a target selector like .article a[data-id="XXXX"] where the ID is the post's ID whose title is changing (not the split test post's ID).