How to reproduce:
1. Open the “AtlasSandbox.zip“ project
2. Select the “Sprites/Atlas1“ SpriteAtlas in the Project tab
3. Drag any one of the Sprites in the “Sprites“ folder in the Project tab onto the “Objects for Packing“ header in the Inspector
4. Click on “Pack Preview“ in the Inspector
5. Observe the Console

Expected result: A message “CHANGED“ is logged indicating a projectChanged event is being triggered
Actual result: No message is logged

Reproducible in: 2021.3.43f1, 2022.3.47f1, 6000.0.20f1

Reproduced on: Windows 11 Pro (23H2)
Not reproduced on: No other environment tested

Notes:
- In 2021.3.43f1 the Scene does not become dirty (has unsaved changes)
- In 2021.3.43f1, and 2022.3.47f1 If the Atlas is unselected and reselected without packing the preview, the “Pack Preview“ button will get grayed out
- In 6000.0.20f1, an “Unsaved Changes Detected“ dialog box pops up, if the preview is not packed and the Atlas is unselected