Lingering potions become splash potions on world reload

Verification builds: 1.2.9 (624178)

Summary: Upon leaving and rejoining a world, all lingering potions will become splash potions.

Impact: Lingering potions are unusable in any situation which involves them existing long-term. This is particularly unfortunate given that they make much more lag-efficient marker entities than mobs do.

Repro Steps:

1. Open the attached world and activate the dispenser to create a lingering potion.
2. Close the world.
3. Open the world again; the lingering potion will now be a splash potion.

Observed Results: The lingering potion turned into a splash potion.

Expected Results: The lingering potion should remain as-is.

Screenshots/Videos attached: No

Notes: Attached world with a behavior pack that does nothing but keep potions from falling to make repro easier; the bug occurs on worlds with no behavior packs as well.