Custom projectile entities use inconsistent physics

*Partner Rank:*

3

*Partner Team Reporting:*

Everbloom Studios

*Verification builds:*

1.13.0.10

*Summary:*

Custom entities that have the minecraft:projectile component use physics that differ from vanilla projectiles'. This is especially visible when the projectiles are shot by an entity with the custom projectile's identifier in the shooter component.

*Impact:*

We are unable to create custom projectile entities that behave like vanilla projectiles and appear the way we want them, and instead have to override a vanilla projectile.

*Repro Steps:*

1. Create and join the provided world, and observe the skeletons shoot at the iron golem. The iron golem has been modified to not take damage, so projectiles fly through it for demonstration.
2. Observe the two skeletons shoot their projectiles through the iron golem. One of them shoots vanilla arrows, the other shoots a custom entity with an identical server entity definition to the vanilla arrows (it looks like a bat).

*Observed Results:*

The arc of both projectiles is different, and the custom projectile lands much shorter than the vanilla arrows.

*Expected Results:*

The player's hitbox should reset after landing, whether they have an elytra or not.

*Screenshots/Videos attached: Yes/No*

Yes

*Regression Builds:*

Unknown

*Notes:*

Video (exceeded maximum file size, so here it is on YouTube)