Items equipped to hands are not counted by q.equipment_count

The query q.equipment_count does not count items equipped to either a mob’s main hand or its off-hand.

Steps to reproduce

1. Load a world with Test Mob.mcpack. This pack adds an animation to bats that makes them spawn a codfish when q.equipment_count is 1 or greater.
2. Spawn a bat and run /replaceitem entity @e[type = bat] slot.weapon.mainhand 0 iron_sword
3. Spawn a bat and run /replaceitem entity @e[type = bat] slot.weapon.offhand 0 shield
4. Spawn a bat and run /replaceitem entity @e[type = bat] slot.armor.head 0 golden_helmet

Expected result

Each bat spawns a codfish.

Observed result

The bats in steps (2)-(3) do not spawn codfish. Only the bat in step (4) spawns a codfish.