Add a special goal: "WP Form Completions"

[RobertJoonas]

Changes

https://3.basecamp.com/5308029/buckets/32037438/card_tables/cards/6013863433#__recording_8250028578

Adds a new special goal (WP Form Completion) with a special property (path). This will behave exactly the same as the 404 goal (that has the path property too):

• It will be included in the full Plausible CSV export (imported_custom_events.csv) with the path prop
• it will be included from imported data in stats queries if it exists (from imports where it doesn't, e.g. GA4, we will silently not return any data for this goal)
• In the dashboard, clicking on the goal in the goals breakdown, the "special goal contents" will pop up in the conversions tab:

Tests

• Automated tests have been added

Changelog

• Entry has been added to changelog

Documentation

• Docs have been updated

Dark mode

• This PR does not change the UI

[aerosol]

LGTM, just one comment wrt potentially better coverage

[aerosol]

Maybe worth adding it also to the remaining tests mentioning "WP Search Query" for example?

I'm seeing props_test.exs and query_imported_test.exs

[RobertJoonas]

added to props_test.exs - b343599.

In query_imported_test.exs it's already covered via for goal_name <- Plausible.Imported.goals_with_url() do ...