Update how-to-safely-rollout-managed-endpoints.md

Explain mirror traffic behavior when invoking while specifying deployment.

Author: dem108

articles/machine-learning/how-to-safely-rollout-managed-endpoints.md

@@ -121,9 +121,13 @@ az ml online-endpoint update --name $ENDPOINT_NAME --mirror-traffic "green=10"
 > [!IMPORTANT]
 > Mirroring has the following limitations:
 > * You can only mirror traffic to one deployment.
-> * A deployment can only be set to live or mirror traffic, not both.
 > * Mirrored traffic is not currently supported with K8s.
 > * The maximum mirrored traffic you can configure is 50%. This limit is to reduce the impact on your endpoint bandwidth quota.
+> 
+> Also note the following behavior:
+> * A deployment can only be set to live or mirror traffic, not both.
+> * You can send traffic directly to the mirror deployment by specifying the deployment set for mirror traffic.
+> * You can send traffic directly to the live deployment by specifying the deployment set for live traffic, but in this case the traffic won't be mirrored to the mirror deployment. Mirror traffic is routed from traffic sent to endpoint without specifying the deployment. 
 
 :::image type="content" source="./media/how-to-safely-rollout-managed-endpoints/endpoint-concept-mirror.png" alt-text="Diagram showing 10% traffic mirrored to one deployment.":::