[BUG] Its possible to put items inside history menu

[Kryniowesegryderiusz]

Description

It is possible to just put items into empty slots in history menu

Steps to reproduce

type /qs history or open it by shop panel

Expected Behaviour

Panel should be fully protected

Screenshots

/quickshop paste URL

https://ghost-chu.github.io/quickshop-hikari-paste-viewer/?remote=https%3A%2F%2Fbytebin.lucko.me%2FVOXFAgycc7

Additional Context

No response

Checklist

• [X] I'm running Paper or Spigot, and not a fork
• [ ] I confirm that Paper/Spigot has been updated to the latest build
• [X] I confirm that QuickShop-Hikari has been updated to the latest stable version released on Modrinth (or the latest CI version)
• [ ] I confirm that I have not read these checkboxes and therefore I just ticked them all.
• [X] I confirm that I'm using QuickShop-Hikari, not QuickShop-Reremake, and I'm well aware that they're maintained by different people, and that Reremake issues shouldn't be reported here.
• [X] I confirm that I am running a server that is not a Hybird Server, (e.g. Mohist, Magma, CatServer, Banner, etc.), and I am aware that QuickShop-Hikari may not function properly on a Forge/Fabric hybrid server, and I am running at my own risk on such a server program, and I am aware that the I run such server-side programs at my own risk and know that I will not receive any support or help for this behavior.
• [X] I am well aware that if the Issue Ticket is not filled out correctly and completely, it will simply be closed without any response or reason.

[Kryniowesegryderiusz]

@Ghost-chu its still possible to put items inside, just not to remove them now