fix(scene): never answer GetMapRotationData with an empty ScRsp

Client session 02:20 died in AdventurePhase._EnterStep1_InitializeMapInfo
('AdventureModule should not be null' -> RuntimeGroupManager
_InitMissionToLegacyGroupRelation NRE) and never left the loading screen.

The 01:00 session reached the scene when this request was dropped; the
empty reply added in the auto-empty round put the client into map-rotation
mode with a null state. Drop it again until real RotaterData is built.

internal/gameserver/dispatch.go

@@ -124,6 +124,12 @@ func isDangerCmd(cmdID uint16) bool {
 	case 4143, 4146, 8541, 5410, 5449, 7142, 3174, 9252, 8175:
 		return true
 	}
+	// GetMapRotationData: an empty reply NREs the client's map init
+	// (AdventurePhase._EnterStep1_InitializeMapInfo) - drop until real
+	// RotaterData is implemented
+	if cmdID == 6827 {
+		return true
+	}
 	return false
 }