What has been done in this MR?

Added the collapsible sidestone/menu stone functionality back to the client, because of... an unset varp!
Finally solved this bug. Basically, we weren't setting the Tutorial Island varp (281), and when it is set to a value of 1000 (which is signifying that the player has completed the tutorial), it allows the menu stones to properly collapse on click.
NOTE: Accounts prior to this fix won't be modified! I sent this fix over to some of the 09 devs a few months back and hadn't seen it resurface in the upstream, so I'm making this MR in order to increase visibility, and have someone capable create a fix to patch prior accounts with the correct varp setting.

This MR is sent as-is, no further modification will be made by myself.

What should testers check?

Complete tutorial (via skip or otherwise), and on the mainland, check if you can "close" the menu side stones. Just click the Backpack icon on/off, and if it works, the rest of them should follow suit!

I have tested these changes thoroughly.
I used the relevant Zaros tool for any JSON edits where possible, and have attached screenshots of any changes.