Fix empty spawn name handling in SpawnCommand

Author: OneLiteFeather

src/main/java/de/theshadowsdust/ultimatespawn/command/SpawnCommand.java

@@ -38,6 +38,7 @@ public SpawnCommand(@NotNull UltimateSpawnPlugin plugin) {
     public void executeSpawnCommand(Player player, final @Argument(value = "name", suggestions = "spawn_names") @Greedy String name) {
 
         String positionName = name == null ? "spawn" : name;
+        if (positionName.isEmpty()) positionName = "spawn";
 
         try {
             SpawnPosition spawnPosition = this.plugin.getSpawnPositionService().getSpawnPosition(positionName).get();