Merged PR 3272: Expose Churn Rates into Main KPIs

# Description

Exposes Churn Rates into Main KPIs, specifically Revenue Churn Rate, Bookings Churn Rate and Listings Churn Rate. This is based on the average approach.

Additionally, it adds these 3 metrics in the kpis_additive_metrics_per_dimension_are_consistent test.
Additionally, it removes from int_mtd_vs_previous_year_metrics the computation of the additive Churn Rates. The removal of further unused code will be handled in a separated PR.

# Checklist

- [X] The edited models and dependants run properly with production data.
- [X] The edited models are sufficiently documented.
- [X] The edited models contain PK tests, and I've ran and passed them.
- [NA] I have checked for DRY opportunities with other models and docs.
- [NA] I've picked the right materialization for the affected models.

# Other

- [ ] Check if a full-refresh is required after this PR is merged.

Related work items: #22691

tests/kpis_additive_metrics_per_dimension_are_consistent.sql

@@ -48,6 +48,9 @@ the Global dimension.
     "Damage Host-Waiver Payments",
     "Waiver Revenue",
     "Waiver Retained",
+    "Revenue Churn Rate",
+    "Bookings Churn Rate",
+    "Listings Churn Rate",
 ) %}
 
 with