Merged PR 4326: Remove cancelled Bookings. Adds index in mtd_aggregated_metrics

# Description

Main changes:
* Remove Cancelled Bookings previous logic.
* Speeds up Main KPIs by adding a couple of indexes in `mtd_aggregated_metrics`. Tested in prod, to me it looks like it's quite fast now.

# 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: #24637

models/intermediate/cross/int_mtd_vs_previous_year_metrics.sql

@@ -30,19 +30,6 @@ with
             dimension in ('global', 'by_number_of_listings', 'by_billing_country')
             and dimension_value <> 'UNSET'
     ),
-    cancelled_bookings as (
-        select *
-        from {{ ref("int_kpis__agg_mtd_cancelled_bookings") }}
-        where
-            dimension in ('global', 'by_number_of_listings', 'by_billing_country')
-            and dimension_value <> 'UNSET'
-        union all
-        select *
-        from {{ ref("int_kpis__agg_monthly_cancelled_bookings") }}
-        where
-            dimension in ('global', 'by_number_of_listings', 'by_billing_country')
-            and dimension_value <> 'UNSET'
-    ),
     billable_bookings as (
         select *
         from {{ ref("int_kpis__agg_mtd_billable_bookings") }}
@@ -205,7 +192,6 @@ with
             check_out_bookings.cancelled_check_out_bookings_rate,
 
             -- OTHER BOOKINGS --
-            cancelled_bookings.cancelled_bookings,
             billable_bookings.billable_bookings,
 
             -- GUEST JOURNEYS --
@@ -399,11 +385,6 @@ with
             on d.date = check_out_bookings.end_date
             and d.dimension = check_out_bookings.dimension
             and d.dimension_value = check_out_bookings.dimension_value
-        left join
-            cancelled_bookings
-            on d.date = cancelled_bookings.end_date
-            and d.dimension = cancelled_bookings.dimension
-            and d.dimension_value = cancelled_bookings.dimension_value
         left join
             billable_bookings
             on d.date = billable_bookings.end_date
@@ -497,7 +478,6 @@ select
     {{ calculate_safe_relative_increment("cancelled_check_out_bookings_rate") }},
 
     -- OTHER BOOKINGS --
-    {{ calculate_safe_relative_increment("cancelled_bookings") }},
     {{ calculate_safe_relative_increment("billable_bookings") }},
 
     -- GUEST JOURNEYS --