refactor: FTRS-1627 Remove unused import and update Vale vocabulary

Author: prjh2-nhs

scripts/config/vale/styles/config/vocabularies/words/accept.txt

@@ -2,6 +2,7 @@
 (?i)Github
 (?i)hotfix
 (?i)Jira
+(?i)Populator
 (?i)Pydantic
 (?i)vpc
 (?i)vpn
@@ -138,4 +139,4 @@ vault_lock_type
 backup_copy_vault_account_id
 backup_copy_vault_arn
 dynamodb
-project_name
+project_name

services/data-migration/tests/unit/version_history/test_utils.py

@@ -1,6 +1,5 @@
 """Unit tests for version history utility functions."""
 
-from decimal import Decimal
 from typing import Any, Dict
 
 import pytest