Air block and item models define the missing texture as the particle texture instead of something that makes sense

Discovered while testing MC-270529 and MC-276725.

The bug

As of 24w45a, the models for air now define minecraft:missingno as their particle texture, presumably to reduce log errors with the fix to MC-236295. This is not ideal, as the missing texture should only appear when there is a genuine issue with resources.

How to reproduce

1. /particle minecraft:block_marker{block_state:{Name:"minecraft:air"}} ~ ~1 ~

2. /give @s cookie[item_model="minecraft:air"]

   , eat this item

Expected results

The missing texture would not be used.

Actual results

It is.

How to fix

This is very easy to fix - we just need to make air use a real texture. I've attached a resource pack that introduces a simple texture for air, and repointed the air model to use it instead. This fixes this issue entirely. I give Mojang full permission to use these assets to fix this issue if needed.