[Enhancement] Downgrade expected network/auth errors to WARN level

[abarghoud]

Criticité : 🟢 Faible (Uniquement de l'observabilité)
Occurrences (sur 28 j) : ~15 occurrences

Description of the issue
Our error logs are being polluted by expected behaviors:

1. AuthService logs invalid signature and invalid token as ERROR when validating or refreshing JWTs.
2. TelemetryConfigService logs context deadline exceeded as ERROR when the Tesla Fleet API times out.

Expected Behavior
These are expected external behaviors and should be logged at WARN or DEBUG level to keep our ERROR alerts focused on actionable internal bugs.