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/reporting/general/mtd_aggregated_metrics.sql

@@ -1,5 +1,14 @@
 {% set production_dimensions = get_kpi_dimensions_for_production() %}
 
+{{
+    config(
+        materialized="table",
+        indexes=[
+            {"columns": ["dimension"]},
+            {"columns": ["dimension", "date"]},
+        ],
+    )
+}}
 with
     dimensions as (
         {% for dimension in production_dimensions %}