Don't show a scary chat error for non-critical update/MOTD check failures

[kovalancik06-max]

Summary

• Fixes Error #31 and Error Check logs #33 (duplicate reports) — players see a red Dungeon Rooms: An error has occured. See logs for more details. chat message on every Hypixel connect.
• Root cause: the background thread in onServerConnect fetches the latest GitHub release (update check) and a MOTD gist over plain HttpURLConnection. On clients with an outdated bundled Java trust store, this throws SSLHandshakeException: PKIX path building failed (see both issues' attached logs, identical stack trace at DungeonRooms.java:247).
• That's a non-critical, cosmetic check — it doesn't affect the mod's actual dungeon-solving functionality — but the generic catch block surfaced it as an alarming, unactionable red error every single session.

Fix

• Replace the chat message + printStackTrace() with a quiet logger.warn(...) call. The failure is still visible in the log file for anyone who wants to investigate, but no longer interrupts/alarms players for something they can't fix and that doesn't matter.

Test plan

• Confirmed both issues share the exact same stack trace and originating line.
• Change is a minimal, mechanical replacement of one statement with another using the already-imported Logger field (logger.warn(String, Throwable)), no new imports/behavior elsewhere.
• Not able to do a full ForgeGradle 1.8.9 build in this environment (requires Java 8 + downloading the full MC/Forge dependency set), so please double check it compiles on your end — the change is intentionally minimal to keep that risk low.