Merged PR 2996: Activate one test, prepare the other

# Description

There were two tests for `int_core__verification_payments` awaiting activation because the source master data had issues that needed to be fixed.

This PR activates the test for `is_missing_user_country` because the dash team has already fixed the problematic country data.

The other test remains turned off because we still have a master data issue (missing VAT rate for Kosovo), but I've already added a missing where condition, and a reference to the ticket where we are tracking the master data issue.

# 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.

activate one test, prepare another but keep it commented

Related work items: #20043

models/intermediate/core/schema.yml

@@ -1128,13 +1128,12 @@ models:
               If this turns true in any other case, you should really find out 
               why the guest doesn't have a billing country.
 
-            # should be uncommented once this ticket gets solved:
-            #tests:
-            #  - not_null
-            #  - accepted_values:
-            #      values:
-            #        - false
-            #      where: are_user_details_deleted != true or are_user_details_deleted is not null
+            tests:
+              - not_null
+              - accepted_values:
+                  values:
+                    - false
+                  where: (are_user_details_deleted != true and are_user_details_deleted is not null)
 
           - name: is_missing_vat_rate_for_country
             data_type: boolean
@@ -1149,12 +1148,13 @@ models:
               If this turns true in any other case, you should really find out 
               what's happening.
 
-            # should be uncommented once this ticket gets solved:
+            # should be uncommented once this ticket gets solved: https://guardhog.visualstudio.com/Data/_boards/board/t/Data%20Team/Stories/?workitem=22148
             #tests:
             #  - not_null
             #  - accepted_values:
             #      values:
             #        - false
+            #      where: (are_user_details_deleted != true and are_user_details_deleted is not null)
 
           - name: are_user_details_deleted
             data_type: boolean