Improvement - Add TransferModule#ping validation & increase PingRequest timeout to 10s

[ItsNature]

Overview

Description:
Fixes the server ping round-trip failing whenever a request contains an unreachable address. The client pings every address and reports unreachable ones as TIMED_OUT. Additionally, requests with more than 10 server IPs were silently dropped by the client and only surfaced as a generic timeout.

Changes:

• PingRequest overrides the timeout to 10s, giving ping round-trips the headroom they need.
• TransferModuleImpl#ping now fails fast with IllegalArgumentException when the request contains no server IPs or more than TransferModule.MAX_PINGS_PER_PACKET (10), instead of sending a request the client can't honor.

---

Review Request Checklist

• Your code follows the style guidelines of this project.
• I have performed a self-review of my code.
• I have tested this change myself. (If applicable)
• I have made corresponding changes to the documentation. (If applicable)
• The branch name follows the projects naming conventions. (e.g. feature/add-module & bugfix/fix-issue)

---