Splash potions and lingering potions ignore custom model particle

Relates to MC-276764 and MC-276765.

The bug

If a splash potion is given a custom model, the smashed glass textures will not inherit the particle textures of that model.

How to reproduce

1. /give @s minecraft:splash_potion[minecraft:item_model=blue_concrete,potion_contents=healing]

2. Throw on ground
3. Observe the white smashed glass particles

Expected results

No white particles - they would instead be blue concrete particles.

Actual results

There are still white particles.

How to fix

Since splash potions and lingering potions produce two types of item particles, one from the "bottle" texture and one from the "contents" texture, it may be worth implementing some sort of system for block and item particle textures that permits multiple particle textures per model, possibly with a weighting system.