Using the command "/execute in minecraft:[dimension] run tp [player] ~ ~ ~" in order to switch dimensions causes the player to fall even when flying in creative mode.

This behaviour does not affect the 1.21 Pre-Release versions, only 1.20.6 and versions prior.

Steps to reproduce:

1. Make sure the player is flying before proceeding with the following steps.
2. Use the command "/execute in minecraft:[dimension] run tp [player] ~ ~ ~" to teleport the player to another dimension, replacing "[dimension]" with the desired dimension and "[player]" with the player's name.
3. Observe that the playing falls after the teleport is complete, despite the player flying when the command was executed.