Built-in Layout options appear missing in the 'Layout' dropdown which is as follows
1] 2 by 3
2] 4 Split
3] Wide
4] Tall
Refer attached video.

Steps to reproduce:
1. Create a new project
2. Select Layout Dropdown

Actual Result:
Built-in Layout options are not available in the 'Layout' dropdown.

Expected Result:
Built-in Layout options should present in Layout Dropdown.

Reproducible with:
2021.2.0a15

Not Reproducible with:
2021.2.0a14, 2021.2.0a1, 2021.1.5f1, 2020.3.5f1, 2019.4.25f1

Environment:
Occurring on Windows 10 & macOS 10.15.