chore: don't query for None

Signed-off-by: Mike Fiedler <miketheman@gmail.com>

Author: miketheman

warehouse/admin/views/malware_reports.py

@@ -212,7 +212,9 @@ def malware_reports_detail(request):
     Show a detailed view of a Malware Report.
     """
     observation_id = request.matchdict.get("observation_id")
-    observation = request.db.get(Observation, observation_id)
+    observation = (
+        request.db.get(Observation, observation_id) if observation_id else None
+    )
 
     return {"report": observation}