"replace" operation of "copy_custom_data" item modifier does not work on root tag

For an item modifier, using "copy_custom_data" with "op" set to "replace" and "target" set to "{}" (aka the root NBT) will not work at all. No error message is displayed, either.

It works correctly if "op" is set to "merge".

Why this needs to be fixed:
Currently, this is the only way to remove any form of NBT data currently exists in a player.
(by putting the item tag data on a storage, remove it in the storage then using copy_custom_data on said storage to root NBT - it's wonky but it works in theory).

If this is not fixed, please add a way to remove NBT for players directly (which would be alot better). Thanks!

How to reproduce

1. Run /data modify storage 236544:test custom_data set value {test:1}

2. Hold an item in your main hand

3. Run:

   /item modify entity @s weapon {function:copy_custom_data,source:{type:storage,source:"236544:test"},ops:[{source:custom_data,target:"{}",op:replace}]}

4. Run /data get entity @s SelectedItem.components."minecraft:custom_data"
   ❌ The minecraft:custom_data component doesn’t exist on the item

5. Run the same command as in Step 3, but with the merge operation instead of replace:

   /item modify entity @s weapon {function:copy_custom_data,source:{type:storage,source:"236544:test"},ops:[{source:custom_data,target:"{}",op:merge}]}

6. Run /data get entity @s SelectedItem.components."minecraft:custom_data"

   ✅ The minecraft:custom_data component is now {test:1}