Fix rare NPE

bukkit/src/main/java/me/caseload/knockbacksync/BukkitBase.java

@@ -2,6 +2,7 @@ package me.caseload.knockbacksync;
 
 import com.github.retrooper.packetevents.PacketEvents;
 import com.github.retrooper.packetevents.manager.server.ServerVersion;
+import com.github.retrooper.packetevents.protocol.world.Location;
 import io.github.retrooper.packetevents.factory.spigot.SpigotPacketEventsBuilder;
 import me.caseload.knockbacksync.event.events.ConfigReloadEvent;
 import me.caseload.knockbacksync.event.KBSyncEventHandler;
@@ -26,6 +27,7 @@ import org.bukkit.entity.Player;
 import org.bukkit.event.Listener;
 import org.bukkit.plugin.PluginManager;
 import org.bukkit.plugin.java.JavaPlugin;
+import org.bukkit.util.Vector;
 import org.incendo.cloud.bukkit.CloudBukkitCapabilities;
 import org.incendo.cloud.execution.ExecutionCoordinator;
 import org.incendo.cloud.paper.LegacyPaperCommandManager;

common/src/main/java/me/caseload/knockbacksync/player/PlayerData.java

@@ -305,7 +305,7 @@ public class PlayerData {
     }
 
     public void quitCombat() {
-        combatTask.cancel(); // should do nothing
+        if (combatTask != null) combatTask.cancel(); // rarely throws NPE without null check
         combatTask = null;
         CombatManager.removePlayer(uuid);
     }