Account for backpack item in curios slot

[Nik77x]

In my previous PR the code I used to get the backpack item returned nothing when it was placed in the curios slot. This because sophisticated backpacks did some custom rendering things that are not needed to render it on the dragon.
This PR replaces that code, this time it checks just the curios back slot (if curios is loaded) and the chest slot.

[seelderr]

Does this code also respect toggling the visibility of the item off in curios?

[Nik77x]

Yes it does!

DragonSurvival/src/main/java/by/dragonsurvivalteam/dragonsurvival/compat/sophisticatedBackpacks/DragonBackpackRenderLayer.java

Lines 153 to 154 in fab6194

	if(!backpackItem.slotContext().visible())
	continue;

If it's not visible it skips the slot.