revert: drop juror get_index only_active passthrough (moved to #571)

This behavioral fix belongs to #571 (juror round listing), not the buildservice
migration. Restores master's only_active=True to keep #564 infra-only.

Refs #571
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: lgelauff

montage/juror_endpoints.py

@@ -83,7 +83,7 @@ def get_index(user_dao, only_active=True):
     Summary: Get juror-level index of active campaigns and rounds.
     """
     juror_dao = JurorDAO(user_dao)
-    counts = juror_dao.get_all_rounds_task_counts(only_active=only_active)
+    counts = juror_dao.get_all_rounds_task_counts(only_active=True)
     stats = [make_juror_round_details(rnd, rnd_stats, ballot)
              for rnd, rnd_stats, ballot in counts]
     return stats