Add isForceDefaultGameMode method (#12673)

paper-server/src/main/java/org/bukkit/craftbukkit/CraftServer.java

@@ -2295,6 +2295,11 @@ public final class CraftServer implements Server {
         }
     }
 
+    @Override
+    public boolean forcesDefaultGameMode() {
+        return this.console.getProperties().forceGameMode;
+    }
+
     @Override
     public ConsoleCommandSender getConsoleSender() {
         return this.console.console;