Unsafe recommendation when handling rollbacks

[AntonAndell]

Describe the bug
When handling call messages a connection can pretend to be sending for a xCall with the same networkId as the receiving chain, thus making the message look like a rollback. And in the md we say the dapps can trust the protocols of rollback.

Expected behavior
Rollbacks should always be trusted to have been delivered by the same protocols you sent it with. And no one should be able to pretend to be from the networkId of the chain who is receiving messages