ExtShape Sinytra Connector Fix

This is a fork of Extended Block Shapes, fixing the bug while used with Sinytra Connector on 1.20.1 Forge.

The latest code in the original mod used its own mixin, which caused crashes in the test environment. This fork switches to the mixin used in the Fabric API.

This fork will be hidden as soon as the original mod is updated and this bug is fixed.