players in parties that quit is buggy sometimes

[DevvyDont]

too lazy to fix this rn so personal note

java.util.ConcurrentModificationException: null
        at java.util.ArrayList$Itr.checkForComodification(Unknown Source) ~[?:1.8.0_211]
        at java.util.ArrayList$Itr.next(Unknown Source) ~[?:1.8.0_211]
        at io.github.devvydoo.levelingoverhaul.managers.PartyManager.disbandParty(PartyManager.java:50) ~[?:?]
        at io.github.devvydoo.levelingoverhaul.managers.PartyManager.removePlayerFromParty(PartyManager.java:36) ~[?:?]
        at io.github.devvydoo.levelingoverhaul.managers.PartyManager.onPlayerLeave(PartyManager.java:93) ~[?:?]
        at com.destroystokyo.paper.event.executor.asm.generated.GeneratedEventExecutor195.execute(Unknown Source) ~[?:?]
        at org.bukkit.plugin.EventExecutor.lambda$create$1(EventExecutor.java:69) ~[patched_1.15.2.jar:git-Paper-237]
        at co.aikar.timings.TimedEventExecutor.execute(TimedEventExecutor.java:80) ~[patched_1.15.2.jar:git-Paper-237]
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:70) ~[patched_1.15.2.jar:git-Paper-237]
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:607) ~[patched_1.15.2.jar:git-Paper-237]
        at net.minecraft.server.v1_15_R1.PlayerList.disconnect(PlayerList.java:466) ~[patched_1.15.2.jar:git-Paper-237]
        at net.minecraft.server.v1_15_R1.PlayerConnection.a(PlayerConnection.java:1533) ~[patched_1.15.2.jar:git-Paper-237]
        at net.minecraft.server.v1_15_R1.NetworkManager.handleDisconnection(NetworkManager.java:386) ~[patched_1.15.2.jar:git-Paper-237]
        at net.minecraft.server.v1_15_R1.ServerConnection.c(ServerConnection.java:163) ~[patched_1.15.2.jar:git-Paper-237]
        at net.minecraft.server.v1_15_R1.MinecraftServer.b(MinecraftServer.java:1328) ~[patched_1.15.2.jar:git-Paper-237]
        at net.minecraft.server.v1_15_R1.DedicatedServer.b(DedicatedServer.java:430) ~[patched_1.15.2.jar:git-Paper-237]
        at net.minecraft.server.v1_15_R1.MinecraftServer.a(MinecraftServer.java:1157) ~[patched_1.15.2.jar:git-Paper-237]
        at net.minecraft.server.v1_15_R1.MinecraftServer.run(MinecraftServer.java:946) ~[patched_1.15.2.jar:git-Paper-237]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_211]