manual_session: avoid risky op when all attempts to manual connect fail

Simply exit the manual session when we fail to connect
manual_attempt_limit times. Marking as suspend could panic if the host
has been received via the seedsync/ protocoladdr process and is currently
in an incompatiable state.

src/net/session/manual_session.rs

@@ -199,9 +199,6 @@ impl ManualSession {
             addr, attempts,
         );
 
-        // Mark this peer as Suspend, which sends it to the Refinery for processing.
-        self.p2p().hosts().try_register(addr.clone(), HostState::Suspend).await.unwrap();
-
         Ok(())
     }
 }