set_pinv(pinv()) clears EntityTag values

CommandHelper seems to not support EntityTag for ItemStacks, resulting in that information being lost when updating the inventory using:
```
set_pinv(pinv())
```
I guess this is similar to #1343 (BlockStateTag)

Tested on:
> CommandHelper-3.3.5-b309
> Purpur-1.19.3-b1895

___

**Test item 1:**
```
/give @s minecraft:item_frame{EntityTag:{Invisible:1b}}
```
Places an invisible item frame.
After `set_pinv(pinv())` it will remove the invisible tag and place a normal item frame. Also applies to glow_item_frame.

**Test item 2:**
```
/give @s minecraft:polar_bear_spawn_egg{EntityTag:{id:"minecraft:iron_golem", CustomName:'{"text":"Jerry"}', CustomNameVisible:1b}}
```
Looks like a polar bear spawn egg but spawn an iron golem named Jerry. right-clicking a spawner makes it an iron golem spawner.
After `set_pinv(pinv())` it turns into a normal polar bear spawn egg.

With 1.20 experimental features we now have a vanilla iron_golem_spawn_egg item (and other previously unobtainable eggs), which don't use EntityTag. But this tag can still be used to make the spawned mob have specific traits.

**Test item 3:**
```
/give @s bee_nest{BlockEntityTag:{Bees:[{EntityData:{id:"minecraft:bee"}},{EntityData:{id:"minecraft:bee"}},{EntityData:{id:"minecraft:bee"}}]}}
```
When placed during the day, 3 bees come out of the hive.
After `set_pinv(pinv())` it will remove all the bee information, creating an empty hive. When placed during the day no bees come out.

This item can be obtained in vanilla survival using a silktouch enchanted tool.
Having access to this tag could allow us to check how many bees are in the beenest/hive item.