Clear ExtendedProperties when SubscriptionId or TenantId are changed using Set-AzureRmContext

Author: azdevxps

src/ResourceManager/Profile/Commands.Profile/Models/RMProfileClient.cs

@@ -301,6 +301,7 @@ public IAzureContext SetCurrentContext(string subscriptionNameOrId, string tenan
 
             context.WithTenant(tenant).WithSubscription(subscription);
             _profile.TrySetDefaultContext(name, context);
+            _profile.DefaultContext.ExtendedProperties.Clear();
             return context;
         }