Remove usage of Optional

api/src/main/java/com/velocitypowered/api/proxy/Player.java

@@ -281,5 +281,5 @@ public interface Player extends CommandSource, Identified, InboundConnection,
    *
    * @return the player's client brand
    */
-  Optional<String> getClientBrand();
+  @Nullable String getClientBrand();
 }

proxy/src/main/java/com/velocitypowered/proxy/connection/client/ConnectedPlayer.java

@@ -873,8 +873,8 @@ public class ConnectedPlayer implements MinecraftConnectionAssociation, Player {
   }
 
   @Override
-  public Optional<String> getClientBrand() {
+  public String getClientBrand() {
-    return Optional.ofNullable(clientBrand);
+    return clientBrand;
   }
 
   void setClientBrand(String clientBrand) {