`.gltf` files' `.bin` dependencies aren't copied into `imported_assets`

## Bevy version

0.14.0

## What you did

Tried to load a `.gltf` file with a `.bin` dependency with preprocessing enabled

## What went wrong

Its `.bin` file wasn't copied into `imported_assets`, so the scene doesn't appear. No errors or warnings.

## Additional information

Here's a minimal repro of it working in 0.13: https://github.com/Seldom-SE/testetst/blob/29eeb4d6c5210cf6f9c0b035979281f308e81846/src/main.rs

And here's a minimal repro of the bug in 0.14: https://github.com/Seldom-SE/testetst/blob/1d591976b13f3f4517a787fe5863bffe3ea9bf5a/src/main.rs

And here's the diff between the two: https://github.com/Seldom-SE/testetst/commit/1d591976b13f3f4517a787fe5863bffe3ea9bf5a

Start by comparing the linked 0.13 and 0.14 minimal repros and tracing the asset preprocessing path that handles the .gltf file. Done means the dependent .bin file is copied into imported_assets and the scene loads without errors or warnings.

Written by the indexing model from the issue text.