Removal of 1.8 Hitbox features

### What happened?

All of Skyblocker's 1.8 hitbox features will be removed once Hypixel drops 1.8 support to ensure consistent behaviour with the expectations of the base game and server.

### Screenshots

_No response_

### Log output

_No response_

### Minecraft Version

1.21.11

### Skyblocker Version

skyblocker-5.11.0+1.21.11.jar

### Additional context

_No response_