Reproduction steps:
1. Open the attached project “UTFProject”
2. Open the (menu: Window > General > Test Runner) Window
3. Click the three dots at the top right corner of the Window
4. Select the “OK” button when the Popup Window appears
5. Observe the crash

Expected result: Play mode tests for all assemblies are disabled successfully
Actual result: The Editor crashes

Reproducible with: 1.1.33, 1.3.9 (2022.1.0a7, 2022.3.17f1), 1.4.2 (2023.3.0b1), 2.0.1-pre.18 (2022.3.17f1, 2023.3.0b1)
Not reproducible with: 1.1.33 (2021.3.34f1), 1.3.9(2022.1.0a6, 2023.2.4f1), 2.0.1-pre.18 (2021.3.34f1, 2023.2.4f1)

Reproducible on: macOS(Intel) 14.2.1
Not Reproducible on: Windows 10 Pro 22H2

Notes:
- The crash can be resolved by navigating to <ProjectRoot>/ProjectSettings/ProjectSettings.asset, changing the playModeTestRunnerEnabled property back to 0, and restarting the editor.
- The regression happened in the Editor versions and not the Package itself.