Fix Behaviors property name in channelfactorybehaviors snippet

[Copilot]

ServiceEndpoint exposes endpoint behaviors via .Behaviors, not .EndpointBehaviors. The PR introduced a non-existent property that would fail to compile against WCF client APIs.

Changes

• snippets/csharp/VS_Snippets_CFX/channelfactorybehaviors/cs/client.cs: Corrects factory.Endpoint.EndpointBehaviors.Add(...) → factory.Endpoint.Behaviors.Add(...)

// Before (broken)
factory.Endpoint.EndpointBehaviors.Add(new EndpointBehaviorMessageInspector());

// After (correct)
factory.Endpoint.Behaviors.Add(new EndpointBehaviorMessageInspector());