After a change with how bundled plugins are handled by the Unity Editor, [bundled plugins|https://docs.unity3d.com/Manual/PluginInspector.html] are no longer considered folders and are instead considered as a single file to prevent creating .meta files inside the plugins. These said .meta files inside plugins were an issue for the users, hence the removal, see UUM-9421.

Reproduction steps:
1. Open a project that contains a bundled plugin.
2. Export the bundled plugin into a .unitypackage
2.1. You can do that by right-clicking the .bundle file and select “Export Package…”
2.2. You can also use the Menu Bar, Assets -> Export Package...
3. Select the bundled plugin and complete the export

Expected result: The .bundle file gets exported successfully

Actual result: The files inside the bundled plugin is not inside the exported .unitypackage. If the bundled plugin was the only selection during export, there will be a console error: “Error while exporting package: No assets to export - only folders. Did you mean to use ExportPackageOptions.Recurse?”

Reproducible with: 2020.3.48f1, 2021.3.26f1, 2022.3.0f1, 2023.1.0b19, 2023.2.0a17
Not reproducible with: 2023.1.0a23, ..., 2020.3.47f1
Introduced in: https://github.cds.internal.unity3d.com/unity/unity/pull/19042

Reproducible on: macOS Ventura 13.2.1 (M1 Max), Windows 10

Forum thread regarding the issue: https://forum.unity.com/threads/dylib-bundle-file-not-exporting-to-unity-package.427752/