feat(dbt): further education status where a school has no school record (H4)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

pipeline/transform/models/marts/_marts_schema.yml

@@ -138,7 +138,7 @@ models:
         tests:
           - not_null
           - accepted_values:
-              values: ['report_card', 'graded', 'ungraded']
+              values: ['report_card', 'graded', 'ungraded', 'short']
       - name: current_grade
         tests:
           - accepted_values: