Allays frequently miss items / don't seek out items outside of their line of sight

Allays are unable to seek items unless they can directly see them.  This causes a number of issues with the allays missing or not being able to pick up many items in many situations as demonstrated within an official Minecraft Now Clip here.

Steps to reproduce:

1. summon an allay

2. place a wall between the allay and an item

3. the allay will never pick up that item unless it can directly see it.