feat(l1): don't log an error if we have no node config file when reading known peers

[fmoletta]

Motivation
We shouldn't emit a warning if we have no node config files where to read known peers from. We should log an error if we get an actual error while reading from an existing node config file

Description

• Don't emit a warning if we have no node config file when reading known peers

Closes #3908

[github-actions]

Lines of code report

Total lines added: 7
Total lines removed: 1
Total lines changed: 8

Detailed view

+-----------------------------------+-------+------+
| File                              | Lines | Diff |
+-----------------------------------+-------+------+
| ethrex/cmd/ethrex/initializers.rs | 375   | -1   |
+-----------------------------------+-------+------+
| ethrex/cmd/ethrex/utils.rs        | 171   | +7   |
+-----------------------------------+-------+------+