InventoryClickEvent does not detect middle clicks (Survival mode)

Expected behavior

When printing out the result of event.getClick() during the InventoryClickEvent, I was expecting ClickType.MIDDLE to get printed upon clicking with the mousewheel on an item.

Observed/Actual behavior

Instead, what I've found out is that no matter what one tries doing, ClickType.MIDDLE can never be detected.
Upon middle clicking an item in an inventory (could be any inventory from what I saw), the only click being detected is ClickType.UNKNOWN.
On discord I was initially told that detecting middle clicks isn't supported, though I find it really strange that the only way to get an UNKNOWN click type is through middle-clicking an item in Survival Mode.

Steps/models to reproduce

1. Create a barebones plugin, one which simply listens to the InventoryClickEvent
2. Print out event.getClick()
3. In survival mode, try all types of clicks that are meant to be available (Left, right, shift-left, shift-right, double left, switch hand, number key, drop, ctrl drop, middle click)
4. All click types get printed like expected, except for ClickType.MIDDLE

Plugin and Datapack List

None, simply the above stated barebones plugin.

Paper version

This server is running Paper version 1.21.1-99-master@1bc02e6 (2024-09-25T02:41:02Z) (Implementing API version 1.21.1-R0.1-SNAPSHOT)

Other

No response

Start by reproducing the issue with a barebones plugin that listens to InventoryClickEvent and prints event.getClick() in Survival mode. Trace the InventoryClickEvent and ClickType handling for middle-click input; done when middle-clicking an inventory item reports ClickType.MIDDLE instead of ClickType.UNKNOWN.