bug: peerStore should update ENRs of existing peers in case they change

[gabrielmer]

Problem

If a peer is added to the peer store and it dynamically changes its ENR, our peer store won't update it. It will currently check that the multiaddress and public key are matched to the peerId and that some ENR is saved. If so, we exit early.

This happens in the following lines in addPeer():

nwaku/waku/node/peer_manager/peer_manager.nim

Lines 128 to 133 in 93e9ba2

	if pm.peerStore[AddressBook][remotePeerInfo.peerId] == remotePeerInfo.addrs and
	pm.peerStore[KeyBook][remotePeerInfo.peerId] == remotePeerInfo.publicKey and
	pm.peerStore[ENRBook][remotePeerInfo.peerId].raw.len > 0:
	trace "peer already managed and ENR info is already saved",
	remote_peer_id = $remotePeerInfo.peerId
	return

But if ENR changed, we won't update it and still exit early.

We should check if the ENR has changed and if so, update it in the peer store.