Merged PR 4304: Adds Cancelled and Not Cancelled Created Bookings

# Description

First commit - should be an exact replica of the previous PR on Check-Out:

Adds Cancelled and Not Cancelled Created Bookings as absolute figures. Adds Cancellation Rate only for aggregated models.
I also added the removal of duplicate bookings. Otherwise the rates might be affected, and this should be cleaner anyway.

Second commit:
Small changes on the unique key description of the model for check-out, doesn't impact the model output.

# 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/kpis/int_kpis__agg_mtd_created_bookings.sql

@@ -15,7 +15,11 @@
         {{ dimension.dimension }} as dimension,
         {{ dimension.dimension_value }} as dimension_value,
         -- Metrics --
-        sum(created_bookings) as created_bookings
+        sum(created_bookings) as created_bookings,
+        sum(cancelled_created_bookings) as cancelled_created_bookings,
+        sum(not_cancelled_created_bookings) as not_cancelled_created_bookings,
+        sum(cancelled_created_bookings)
+        / sum(created_bookings) as cancelled_created_bookings_rate
     from {{ ref("int_kpis__metric_mtd_created_bookings") }}
     group by 1, 2, 3, 4
     {% if not loop.last %}