Fix another rare NPE in PingRunnable

Author: Axionize

common/src/main/java/me/caseload/knockbacksync/manager/PlayerDataManager.java

@@ -7,6 +7,7 @@
 import me.caseload.knockbacksync.util.FloodgateUtil;
 import me.caseload.knockbacksync.util.GeyserUtil;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
 
 import java.util.Map;
 import java.util.UUID;
@@ -16,7 +17,7 @@ public class PlayerDataManager {
 
     private static final Map<User, PlayerData> playerDataMap = new ConcurrentHashMap<>();
 
-    public static PlayerData getPlayerData(@NotNull User user) {
+    public static @Nullable PlayerData getPlayerData(@NotNull User user) {
         return playerDataMap.get(user);
     }
 

common/src/main/java/me/caseload/knockbacksync/runnable/PingRunnable.java

@@ -17,7 +17,8 @@ public void run() {
 
         for (User user : CombatManager.getPlayers()) {
             PlayerData playerData = PlayerDataManager.getPlayerData(user);
-            playerData.sendPing(true);
+            if (playerData != null)
+                playerData.sendPing(true);
         }
     }
 }