(Bugfix) NPE on change server

[terminalsin]

Fixes the following:

[22:43:22 ERROR]: Task BungeeTask(sched=net.md_5.bungee.scheduler.BungeeScheduler@35a80a70, id=1140799, owner=de.staticred.discordbot.DBVerifier@c5324529, task=de.staticred.discordbot.bungeeevents.ChangedBukkitServerEvent$$Lambda$1980/0x00000000802d6010@a731b14b, delay=2000, period=0, running=true) encountered an exception
java.lang.NullPointerException: null
        at de.staticred.discordbot.bungeeevents.ChangedBukkitServerEvent.lambda$onServerChange$0(ChangedBukkitServerEvent.java:41) ~[?:?]
        at de.staticred.discordbot.bungeeevents.ChangedBukkitServerEvent$$Lambda$1980/0x00000000802d6010.run(Unknown Source) ~[?:?]
        at net.md_5.bungee.scheduler.BungeeTask.run(BungeeTask.java:66) ~[server.jar:git:Travertine-Bootstrap:1.16-R0.4-SNAPSHOT:72c234b:unknown]
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) ~[?:1.8.0_275]
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) ~[?:1.8.0_275