Reproduction steps:
1. Open the attached “UITK Panel Settings Bug Report.zip” project
2. Create a new UI Document (GameObject → UI Toolkit → UI Document)
3. Click on the created UI Document
4. Observe the assigned “Panel Settings” in the Inspector

Expected result: There is a settings menu that allows to set the default Panel Settings that get assigned to all new UI Documents
Actual result: One of the three of Panel Settings assets in the project gets randomly assigned

Reproducible with: 2021.3.36f1, 2022.3.22f1, 2023.2.16f1, 6000.0.0b13

Reproducible on: Windows 11
Not reproducible on: no other environment tested

Notes:
- Issue appears because when {{AssetDatabase.FindAssets("t:panelsettings", "Assets") }}is called the first Panel Setting found - gets assigned
- More of a productivity issue, since it takes extra steps or time to assign the correct settings every time a new Document, is created
- Issue is more visible when testing with different projects since the same project would usually assign the same setting on every version