fix: remove extra blank line in cron_service imports to satisfy ruff I001

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: FernandezAstor

testgen/common/cron_service.py

@@ -8,7 +8,6 @@
 from testgen.common import date_service
 
 
-
 class CronSample(TypedDict, total=False):
     id: str | None
     error: str | None