Merged PR 4743: Filtered test accounts

# Description

Filtered test accounts according to `Account_type` in Cosmos
Unfortunately this doesn't actually filter all test accounts, there are some that are correctly classified and I will have to ask specifically to either remove or classify correctly

# 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.
- [ ] I have checked for DRY opportunities with other models and docs.
- [ ] I've picked the right materialization for the affected models.

# Other

- [ ] Check if a full-refresh is required after this PR is merged.

Filtered test accounts

Related work items: #28239

models/staging/core/stg_core__apim_user.sql

@@ -1,3 +1,5 @@
+{% set test_account = "TEST" %}
+
 with
     raw_apim_user as (select * from {{ source("core", "ApimUser") }}),
     stg_core__apim_user as (
@@ -15,3 +17,4 @@ with
     )
 select *
 from stg_core__apim_user
+where upper(json_document_user_data ->> 'AccountType') <> '{{ test_account }}'