Update seat-management.mdx

This was incorrect, we look at the last seen value from gateway

Author: kennyj42

src/content/docs/cloudflare-one/identity/users/seat-management.mdx

@@ -11,7 +11,7 @@ The amount of user seats available in your Zero Trust account depends on the amo
 
 ## What constitutes an authentication event
 
-For Access, this is any Cloudflare Access authentication event, like a login to the [App Launcher](/cloudflare-one/applications/app-launcher/) or an application. For Gateway, this means any Cloudflare WARP authentication event, like enrolling a device to your ZT organization.
+For Access, this is any Cloudflare Access authentication event, like a login to the [App Launcher](/cloudflare-one/applications/app-launcher/) or an application. For Gateway, this is if any devices associated have been seen in the specified period.
 
 If either one of these events occurs, that user's identity is added as an Active user to Zero Trust and consumes one seat.