The player cannot collect items in the hitbox of the EnderDragon.

How to reproduce

1. Use the following command (uses the bug reported in MC-90417):

   /summon Boat ~ ~ ~ {Passengers:[{id:EnderDragon}]}
   

2. Drop an item near the EnderDragon
3. Try to collect the item

The item is not a ghost item, once the EnderDragon moved away the player is able to pick the item up.