* test_protocol.nim: enhance test reboot and connect
- Is not necessary to start the node if the switch object has been
already started
- Enable an existing "Relay can receive messages after reboot and
reconnect" test
- Explicit reconnect to peer in "Relay can receive messages after reboot
and reconnect" test
* tests/waku_relay/utils: avoid starting the proto again in newTestSwitch proc
With that, we avoid double start of the protocol.
* bump nim-libp2p