fix: duplicate dictionary key 31 in XID_MESSAGES (#4649)

Signed-off-by: Oviya Seeniraj <oseeniraj@nvidia.com>

tests/fault_tolerance/hardware/fault-injection-service/agents/gpu-fault-injector/gpu_xid_injector.py

@@ -110,7 +110,6 @@ XID_MESSAGES: Dict[int, str] = {
     57: "Clocks Event: Power limit exceeded",
     # Common Graphics XIDs (often seen in test environments)
     13: "Graphics Engine Exception",
-    31: "GPU stopped responding",  # Can be both MMU or timeout context
     45: "Preemptive Cleanup, due to previous errors",
     69: "Graphics Exception: Class Error",
 }