Mace smash attack does not knock back other players when they are not the attacked entity

Using a mace smash attack on an entity when there is a player nearby will not knock back the player.

Steps to Reproduce:

1. With two accounts, log onto an LAN world
2. Provide Player 1 with a mace
3. Have Player 2 stand still
4. Put an armor stand near Player 2
5. Have Player 1 stand near the armor stand, then teleport into the air

   /tp @p ~ ~20 ~
   

6. Before landing, do a smash attack on the armor stand

Expected & Observed Results:

- The attack will knock back any surrounding entities, excluding the player standing nearby.
- The attack would knock back any entities standing near the attacked entity.

Screenshots/Videos:

MaceSmashPlayer.mp4

Notes:

Related to: MC-269400 MC-269502 MC-269377