Added if(vehicle) check (PrismarineJS#3619)

Author: SinanAkkoyun

lib/plugins/entities.js

@@ -813,7 +813,9 @@ function inject (bot) {
       originalVehicle.passengers.splice(index, 1)
     }
     passenger.vehicle = vehicle
-    vehicle.passengers.push(passenger)
+    if (vehicle) {
+      vehicle.passengers.push(passenger)
+    }
 
     if (packet.entityId === bot.entity.id) {
       const vehicle = bot.vehicle