Merged PR 5385: id_deal unique test

# Description

Added unique test for `id_deal` and `id_contact` for `xero_contacts` models.
This should all work after the run

# 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.

id_deal unique test

Related work items: #30809

models/intermediate/xero/schema.yml

@@ -31,6 +31,8 @@ models:
         data_type: character varying
         description: |
           Identifier of the account. It can be null.
+        data_tests:
+          - unique
 
       - name: is_contact_missing_id_deal
         data_type: boolean

models/reporting/xero/schema.yml

@@ -296,6 +296,9 @@ models:
       - name: id_contact
         data_type: character varying
         description: Xero's unique identifier for the contact.
+        data_tests:
+          - not_null
+          - unique
 
       - name: account_number
         data_type: character varying
@@ -309,6 +312,8 @@ models:
 
           You can use this to find specific deal ids or even as a proxy bool to
           keep or remove deal id customers.
+        data_tests:
+          - unique
 
       - name: contact_name
         data_type: character varying