Clarify when ip_risk_snapshot is not populated

Add documentation explaining that the IP risk snapshot is not provided
for low-risk networks, and that a None value indicates either no signals
or low-risk signals for the network.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <[email protected]>

Author: horgh

src/geoip2/records.py

@@ -527,6 +527,11 @@ class Traits(Record):
     responsive to traffic on your network. If you need realtime IP risk scoring
     based on behavioral signals on your own network, please use minFraud.
 
+    We do not provide an IP risk snapshot for low-risk networks. If this field
+    is not populated, we either do not have signals for the network or the
+    signals we have show that the network is low-risk. If you would like to get
+    signals for low-risk networks, please use the minFraud web services.
+
     This attribute is only available from the Insights end point.
     """
     _ip_address: IPAddress | None