`droptransfer` feature shulkerbox nested and `droptransfer` bind to doors, problems leading to loss of items

[thefatwhale]

LWC Version (/lwc admin version):

/lwc admin version
Main plugin: 2.4.0

Server version (/version):

/version
This server is running Paper version git-Paper-497 (MC: 1.20.4) (Implementing API version 1.20.4-R0.1-SNAPSHOT) (Git: d8d54d9 on ver/1.20.4)

Short five word summary of issue:

1 Shulker Box can nested with droptransfer feature.

Detailed description of problem: To reproduce this.

1. Place Shulker Box Block on the ground.
2. use /lwc mode droptransfer select and rightclick to select shulker box.
3. drop your shulker box, It transfer into shulkerbox, nested.

2 droptransfer can bind non-container protection blocks. And remove item if try to drop items.

1. Droptransfer can bind to a protection block even no container.
2. try to drop items, leading to loss items.

To reproduce this.

1. place a oak trapdoor on ground.
2. use /lock to protection this trapdoor.
3. use /lwc mode droptransfer select and right click the trapdoor. to bind
4. try to drop items use Q, item removed by plugin.

I'm trying to modify this part of the code. with issue #238 together.