Merged PR 4941: KPIs refactor Stage 4: Switch onboarding MRR to new KPIs model

# Description

Puts in production the new KPIs model for Onboarding MRR.

The change has been validated with MD5 trick.

# 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.
- [X] I have checked for DRY opportunities with other models and docs.
- [X] 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: #28949

models/intermediate/cross/int_mtd_vs_previous_year_metrics.sql

@@ -174,13 +174,10 @@ with
             dimension in ('global', 'by_number_of_listings', 'by_billing_country', 'by_business_scope')
             and dimension_value <> 'UNSET'
     ),
-    int_monthly_onboarding_mrr_per_deal as (
-        select * from {{ ref("int_monthly_onboarding_mrr_per_deal") }}
+    int_kpis__agg_monthly_onboarding_mrr as (
+        select *
+        from {{ ref("int_kpis__agg_monthly_onboarding_mrr")}}
     ),
-    int_mtd_agg_onboarding_mrr_revenue as (
-        select * from {{ ref("int_mtd_agg_onboarding_mrr_revenue") }}
-    ),
-
     plain_kpi_combination as (
 
         select
@@ -361,8 +358,8 @@ with
             as revenue_retained_post_resolutions_ratio,
 
             -- ONBOARDING MRR METRIC --
-            onboarding_mrr.expected_mrr_per_deal,
-            onboarding_mrr_revenue.expected_mrr
+            onboarding_mrr.onboarding_mrr_per_new_deal_in_gbp as expected_mrr_per_deal,
+            onboarding_mrr.total_onboarding_mrr_in_gbp as expected_mrr
 
         from int_kpis__agg_dates_main_kpis d
         left join
@@ -431,15 +428,10 @@ with
             and d.dimension = churn.dimension
             and d.dimension_value = churn.dimension_value
         left join
-            int_monthly_onboarding_mrr_per_deal onboarding_mrr
+            int_kpis__agg_monthly_onboarding_mrr onboarding_mrr
             on d.date = onboarding_mrr.date
             and d.dimension = onboarding_mrr.dimension
             and d.dimension_value = onboarding_mrr.dimension_value
-        left join
-            int_mtd_agg_onboarding_mrr_revenue onboarding_mrr_revenue
-            on d.date = onboarding_mrr_revenue.date
-            and d.dimension = onboarding_mrr_revenue.dimension
-            and d.dimension_value = onboarding_mrr_revenue.dimension_value
         left join 
             total_and_retained_revenue
             on d.date = total_and_retained_revenue.end_date