In Geth v1.10, we changed the structure of the "les" ENR entry. As a result, the DHT crawler that creates the DNS lists
no longer recognizes the les nodes, which is fixed in this commit. 

* cmd/devp2p: skip ENR field tails properly in nodeset filter
* cmd/devp2p: fix tail decoder for snap as well
* les: fix tail decoding in "eth" ENR entry