Merged PR 4727: Bookings fees are now Old Dashboard Booking Fees in Main KPIs

# Description

Booking fees is widely used with different meanings, for old dash, for new dash, for both, etc. This is painful. First step to align on a proper naming is ensure that what we report in Main KPIs is clearly stated, which in this case, Booking Fees are now called Old Dashboard Booking Fees.

Changes:
* Modify `stg_seed__accounting_aggregations` seed to rename Booking Fees to Old Dashboard Booking Fees. This is for us to clarify. This is only applied for KPIs compute. I also added an empty space that I mistakenly forgot in the past for `financial_l3_aggregation`.
* Modify KPIs source, i.e., `int_kpis__metric_daily_invoiced_revenue`. Here I forcefully modify the name of the field to `xero_old_dashboard_booking_net_fees_in_gbp`.
* Propagate changes of downstream usages of `xero_booking_net_fees_in_gbp` to `xero_old_dashboard_booking_net_fees_in_gbp`. This affects all models, including the reporting model. On this one we still have both names to avoid breaking it. I will need to modify the data glossary in PBI anyway so I'll do this change as well.
* Modify displayed metric name from Booking Fees Revenue to Old Dashboard Booking Fees Revenue.
* Modify schema so it reflects the proper names, descriptions, and tests.
* Ensure outlier and completion tests still work after this change.

I confirm the field `xero_booking_net_fees_in_gbp` does not exist anymore in the rest of DWH after these changes, except for the abovementioned comment on the reporting line.

# 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: #28560

models/reporting/general/monthly_aggregated_metrics_history_by_deal.sql

@@ -95,7 +95,15 @@ select
     end as host_resolution_payment_per_created_booking_ratio,
     case
         when {{ is_date_before_20th_of_previous_month("date") }}
-        then xero_booking_net_fees_in_gbp
+        then xero_old_dashboard_booking_net_fees_in_gbp
+        else null
+    end as xero_old_dashboard_booking_net_fees_in_gbp,
+    -- Following line is a temporary handler to not break reporting.
+    -- We will need this line anyway for the combination of Old and New 
+    -- Dash.
+    case
+        when {{ is_date_before_20th_of_previous_month("date") }}
+        then xero_old_dashboard_booking_net_fees_in_gbp
         else null
     end as xero_booking_net_fees_in_gbp,
     case