chore(): small improvements

src/backend/apps/decision/services.py

@@ -145,7 +145,10 @@ def _check_participation_limits(
     return not recent_completed
 
 
-def _check_domain_conflicts(experiment: Experiment) -> bool:
+def _check_domain_conflicts(
+    experiment: Experiment,
+    subject_id: str,
+) -> bool:
     memberships = ExperimentConflictDomain.objects.filter(
         experiment=experiment,
     ).select_related("conflict_domain")
@@ -154,7 +157,7 @@ def _check_domain_conflicts(experiment: Experiment) -> bool:
         if not resolve_domain_conflict(
             experiment_id=experiment.pk,
             domain_id=membership.conflict_domain_id,
-            subject_id="",
+            subject_id=subject_id,
         ):
             return False
     return True
@@ -219,7 +222,7 @@ def decide_for_flag(
         _persist_decision(result, subject_id)
         return result
 
-    if not _check_domain_conflicts(experiment):
+    if not _check_domain_conflicts(experiment, subject_id):
         DECIDE_REQUESTS.labels(reason="domain_conflict").inc()
         result = {
             "flag": flag_key,