Using elytra to fly into the 30 million barrier continues playing flight sounds loudly

The bug

Discovered while testing MC-198928.

When flying into the 30 million block world border using elytra while using rockets, the elytra flight sound still plays at full volume, even if the player is only moving slightly or not at all. This is inconsistent with the sounds that play while flying into the standard world border.

How to reproduce

1. Run the command /tp @p ~ ~ 29999975

2. Throw an ender pearl so that you cross the world border

3. Equip elytra and hold firework rockets

4. Fly towards the 30 million block barrier, and keep launching more firework rockets to maintain speed

Notice how the elytra flight sound plays loudly.