Add a specific flag for shelf access

### WorldEdit Version

worldedit-bukkit-7.4.0

### WorldGuard Version

worldguard-bukkit-7.0.15

### Platform Version

Paper version 1.21.11-113-main@6103cc7

### Confirmations

- [x] I am using the most recent Minecraft release.
- [x] I am using a version of WorldEdit compatible with my Minecraft version.
- [x] I am using a version of WorldGuard compatible with my Minecraft version.
- [x] I am using the latest or recommended version of my platform software.
- [x] I am NOT using a hybrid server, e.g. a server that combines Bukkit and Forge. Examples include Arclight, Mohist, and Cardboard.
- [x] I am NOT using a fork of WorldEdit, such as FastAsyncWorldEdit (FAWE) or AsyncWorldEdit (AWE)

### Bug Description

Players can put items on shelf

### Expected Behavior

so that players cannot put or take items in regions

### Reproduction Steps

1. place shelf on region when players can't build
2. login on players without OP and use shelf

### Optional WorldGuard-Report

_No response_

### Anything Else?

_No response_