The `whack` and `stab` animation types look identical when holding nothing in first person mode

Relates to MC-310822 and MC-310823.

In third person view, with an empty hand, “whack” and “stab” are correctly distinguished. However, in first version view, they look identical, which they are not supposed to do.

To reproduce:

/swing @s mainhand whack

/swing @s mainhand stab

Expected results: we would see two different hand movements.

Actual results: this is true with the third person camera, but in first person they incorrectly look the same.