WARN bevy_pbr::render::gpu_preprocess: The preprocessing index buffer wasn't present with alien_cake_addict

## Bevy version

The release number or commit hash of the version you're using.
64efd08e13c55598587f3071070f750f8945e28e

## What you did

```
cargo run --features=bevy_dev_tools --features=wayland --example alien_cake_addict
```

## What went wrong

```
Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.42s
Running `target/debug/examples/alien_cake_addict`
2024-12-27T02:01:25.125316Z INFO bevy_diagnostic::system_information_diagnostics_plugin::internal: SystemInfo { os: "Linux 2.17 Gentoo", kernel: "6.6.67-gentoo", cpu: "AMD Ryzen 9 5900HX with Radeon Graphics", core_count: "8", memory: "30.8 GiB" }
2024-12-27T02:01:25.241564Z INFO bevy_render::renderer: AdapterInfo { name: "AMD Radeon RX 6800M", vendor: 4098, device: 29663, device_type: DiscreteGpu, driver: "AMD proprietary driver", driver_info: "(AMD proprietary shader compiler)", backend: Vulkan }
ALSA lib /var/tmp/portage/media-libs/alsa-lib-1.2.13-r1/work/alsa-lib-1.2.13/src/pcm/pcm_dmix.c:1000:(snd_pcm_dmix_open) unable to open slave
2024-12-27T02:01:26.058285Z INFO bevy_winit::system: Creating new window App (0v1)
2024-12-27T02:01:27.716441Z WARN bevy_pbr::render::gpu_preprocess: The preprocessing index buffer wasn't present
2024-12-27T02:01:27.783825Z WARN bevy_pbr::render::gpu_preprocess: The preprocessing index buffer wasn't present
2024-12-27T02:01:27.869169Z WARN bevy_pbr::render::gpu_preprocess: The preprocessing index buffer wasn't present
2024-12-27T02:01:27.985523Z WARN bevy_pbr::render::gpu_preprocess: The preprocessing index buffer wasn't present
2024-12-27T02:01:28.085427Z WARN bevy_pbr::render::gpu_preprocess: The preprocessing index buffer wasn't present
2024-12-27T02:01:28.148302Z INFO bevy_window::system: No windows are open, exiting
2024-12-27T02:01:28.153437Z WARN bevy_pbr::render::gpu_preprocess: The preprocessing index buffer wasn't present
2024-12-27T02:01:28.153885Z INFO bevy_winit::system: Closing window 0v1
2024-12-27T02:01:28.163184Z WARN bevy_pbr::render::gpu_preprocess: The preprocessing index buffer wasn't present
```

Reproduce the report with the alien_cake_addict example and the listed Cargo features. Then inspect bevy_pbr::render::gpu_preprocess around the warning about the missing preprocessing index buffer. Done should establish why the warning occurs and whether it represents an actual rendering problem or an expected condition.

Written by the indexing model from the issue text.