Custom Assets do not use dark theme icons when the Editor Theme is set to dark

How to reproduce:
1. Open the attached project (IconTest.zip)
2. Go to Preferences -> General -> Editor Theme -> set to "Dark"
3. In the Project view, select the Asset "ExampleAsset.cs"
4. In the top left of the Inspector view, click the Select Icon menu
5. Select "Other..." and double-click the "example-icon.png" Texture to select it
6. At the top of the Editor window, go to Assets -> Create -> Example Icon Asset
7. Observe the "New Example Asset" icon in the Project window

Expected result: the dark theme icon (d_example-icon.png) is used for the Asset
Actual result: the light theme icon (example-icon.png) is used for the Asset

Reproducible with: 2019.4.32f1, 2020.3.23f1, 2021.1.28f1, 2021.2.3f1, 2022.1.0a15