Entities do not travel with the player into the portal

[foxya27]

Spark link

https://spark.lucko.me/p14OJb8jr9

Expected behavior

A player on a horse enters a nether portal and teleports there with her, this work on the paper

Observed/Actual behavior

A player on a horse stands in the portal, nothing happens

Steps/models to reproduce

Get on the horse and go into the portal

Purpur version

Current Purpur Version: 1.21-2245-9efd5fc (MC: 1.21)*

• You are running the latest version Previous: git-Purpur-2062 (MC: 1.20.1)

Agreements

• [X] I am running the latest version of Purpur available from https://purpurmc.org/downloads.
• [X] I have searched for and ensured there isn't already an open issue regarding this.
• [ ] I ticked all the boxes without actually reading them
• [X] My version of Minecraft is supported by Purpur.

Other

No response