Proper client timeout detection (#19906)

- Properly detect client timeout when logged into a character after a configurable time (default 60s) has passed without the client sending any packets.
- Fixes issues with crashed clients leaving characters in the world for a very long time (default 15 minutes), as well as edge case exploits involving intentionally pausing client execution for some amount of time.

(cherry picked from commit 7dfd472f8d)

src/server/game/Server/WorldSocket.cpp

@@ -424,7 +424,10 @@ WorldSocket::ReadDataHandlerResult WorldSocket::ReadDataHandler()
             return ReadDataHandlerResult::WaitingForQuery;
         }
         case CMSG_KEEP_ALIVE:
+            sessionGuard.lock();
             LogOpcodeText(opcode, sessionGuard);
+            if (_worldSession)
+                _worldSession->ResetTimeOutTime(true);
             break;
         case CMSG_LOG_DISCONNECT:
             LogOpcodeText(opcode, sessionGuard);
@@ -471,9 +474,8 @@ WorldSocket::ReadDataHandlerResult WorldSocket::ReadDataHandler()
                 break;
             }
 
-            // Our Idle timer will reset on any non PING opcodes.
-            // Catches people idling on the login screen and any lingering ingame connections.
-            _worldSession->ResetTimeOutTime();
+            // Our Idle timer will reset on any non PING opcodes on login screen, allowing us to catch people idling.
+            _worldSession->ResetTimeOutTime(false);
 
             // Copy the packet to the heap before enqueuing
             _worldSession->QueuePacket(new WorldPacket(std::move(packet)));