Easy Shulker Boxes / Mortar Compatibility

Adds compatibility between Easy Shulker Boxes and Mortar (and Pastels).

Very simple datapack that allows Easy Shulker Boxes features to work with Mortar's 8 additional shulker box colors (maroon, scarlet, amber, pear, pine, slate, lavender, salmon) and their bundles.

Only tested on Minecraft Fabric 1.21.5, though it should work on any version.