feat(l1): send ENR optionally on Handshake messages

[ElFantasma]

Motivation
From the spec:

node A compares the enr-seq element of the WHOAREYOU challenge against its own node record sequence number. If the sequence number in the challenge is lower, it includes its record into the handshake message packet.

Description

Checks the sequence number and sends the ENR only if the sequences doesn't match.

depends on #5799

Closes #5777

[github-actions]

Lines of code report

Total lines added: 3
Total lines removed: 0
Total lines changed: 3

Detailed view

+-----------------------------------------------+-------+------+
| File                                          | Lines | Diff |
+-----------------------------------------------+-------+------+
| ethrex/crates/networking/p2p/discv5/server.rs | 507   | +3   |
+-----------------------------------------------+-------+------+