RootCanal: Send AuthenticationComplete only for initiator

The AuthenticationComplete is sent as a response of an Authentication
Request, this mean that only the initiator should receive it

Tag: #testing
Test: gd/cert/run
Signed-off-by: David Duarte <licorne@google.com>
Change-Id: I48e69dc82b466445eaf70e69371aa45f41b06ed4