Bundles take up four slots inside another bundle despite being single stack items

This issue clones MC-207234, which was previously resolved as Invalid due to the reasoning provided by [Mod] Avoma, in that "Bundles can stack up to 16, therefore making them take 4 spaces in a bundle."
Bundles can't stack to 16 in item form, and are single stack items. It would be expected that they take up the entire capacity of another bundle.

Steps to Reproduce:

1. Get 2 bundles
2. Put bundle in bundle

Observed & Expected Results:

- The bundle takes up 4 slots, despite being single stack.
- The bundle would take the entire capacity.

Screenshots/Videos:

Bundleception.mp4

Notes:

Discovered while testing MC-270314