chore(l1): preventing errors to propagate to spawned

[ElFantasma]

Motivation

Error lines in spawned logs were muted because there was a lot of spam regarding failed connections and handshakes. That was not safe as other important problems may get muted too.

Description

This PR handles the connection errors on handshake and initialization and logs a lower priority log line (debug) as it is pretty common.

It also reverts the log directive to mute spawned initialization errors.

it requires spawned 0.2.2.

Closes #3472

[github-actions]

Lines of code report

Total lines added: 38
Total lines removed: 5
Total lines changed: 43

Detailed view

+-----------------------------------------------------------+-------+------+
| File                                                      | Lines | Diff |
+-----------------------------------------------------------+-------+------+
| ethrex/cmd/ethrex/initializers.rs                         | 297   | -5   |
+-----------------------------------------------------------+-------+------+
| ethrex/crates/l2/monitor/app.rs                           | 457   | +3   |
+-----------------------------------------------------------+-------+------+
| ethrex/crates/l2/sequencer/l1_watcher.rs                  | 339   | +2   |
+-----------------------------------------------------------+-------+------+
| ethrex/crates/networking/p2p/rlpx/connection/handshake.rs | 496   | +3   |
+-----------------------------------------------------------+-------+------+
| ethrex/crates/networking/p2p/rlpx/connection/server.rs    | 846   | +30  |
+-----------------------------------------------------------+-------+------+

[tomip01]

Works well!

[fedacking]

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