Commands apply across dimensions

Using a command, such as /kill, without a range modifier will cause the command to affect all dimensions that are currently loaded.

This was introduced in the latest 1.20 update as I'm certain that commands did not work like this previously.

Please see attached video for evidence and a tutorial on how to reproduce the bug.

Steps to Reproduce:
1. Place a repeating command block set to always active in the Overworld
2. Set the command on the block to "kill @e[type=witch]"
3. Have one player stay in the Overworld and another go into the Nether
4. The player in the Nether spawns a witch
5. Observe the witch dies via the command block

Observed Results:
The witch dies via the command block

Expected Results:
The witch should not die via the command block

Notes:
This must happen in a realm or multiplayer world where both dimensions are being rendered and simulated.