Standardise empty string as null / not set

By: md_5 <git@md-5.net>

paper-server/src/main/java/org/bukkit/craftbukkit/util/CraftChatMessage.java

@@ -139,7 +139,7 @@ public final class CraftChatMessage {
     }
 
     public static IChatBaseComponent fromStringOrNull(String message) {
-        return (message == null) ? null : fromString(message)[0];
+        return (message == null || message.isEmpty()) ? null : fromString(message)[0];
     }
 
     public static IChatBaseComponent[] fromString(String message) {