Fixed NPE when party creation doesn't use password. Solves bug reported here: https://discord.com/channels/526933440214597677/526938425161416727/1213131451235827753 (#4981)

Signed-off-by: Momshroom <Momshroom@gmail.com>

src/main/java/com/gmail/nossr50/party/PartyManager.java

@@ -354,7 +354,6 @@ public final class PartyManager {
     public void createParty(@NotNull McMMOPlayer mcMMOPlayer, @NotNull String partyName, @Nullable String password) {
         requireNonNull(mcMMOPlayer, "mcMMOPlayer cannot be null!");
         requireNonNull(partyName, "partyName cannot be null!");
-        requireNonNull(password, "password cannot be null!");
 
         Player player = mcMMOPlayer.getPlayer();