Player stuck in sneaking animation on dimension change

This one is a bit tricky to trigger, but if it happens, it gives the player an advantage of being not seen through walls despite not physically sneaking (unfair for PvP).

If the player is sneaking while being teleported to a different dimension and releases the sneak button the moment they see the "Loading terrain..." screen, they will be stuck in sneaking animation for other players despite being able to walk at normal speed and even sprint.

Demo of the issue

To reproduce:

For the player to get stuck in crouch animation:

1. Be in the opposite dimension to the observer (eg. in The Overworld).
2. Hold the crouch button and walk into the Nether Portal.
3. The moment "Loading terrain..." screen appears, release the crouch button.
4. The observer should see you stuck in crouching animation. Run around to confirm that.

For the observer:

1. Be in the opposite dimension to the player (eg. in The Nether).
2. Watch the player as they appear in the portal.

Notes:

• Animation returns to normal walking mode if the player crouches and stops crouching again.
• Happens while using /tp command as well.
• Not tested in other versions.
• Not tested with the crouch button in toggle mode.

The issue relates to MC-124177 and likely to MC-174026.