UI Builder fails to create StyleSheet with large file name because 'path is outside of the project'

Steps to reproduce:

1. Open a Unity Project
2. Open UI Builder via Window > UI Toolkit > UI Builder
3. In the StyleSheets section, click + > Create New USS
4. Give the uss file a long file name (if its too long Windows won't let you create the file) such as sdfasfaeswfassdfasfaeswfassdfasfaeswfassdfasfaeswfassdfasfaeswfassdfasfaeswfassdfasfaeswfassdfasfaeswfassdfasfaeswfassdfasfaeswfassdfasfaeswfassdfasfaeswfassdfasfaeswfassdfasfaeswfassdfasfaeswfassdfasfaeswfassdfasfaesw
5. Click 'Save'

Actual results: A 'Saving new document failed' warning will be given. The warning says that 'the path is outside of the project' which is incorrect.

You can create a USS file with a file name this long from your Project Window (and then add it to UI Builder via Add Existing USS), it's creating  via UI Builder that has this issue.

Expected results: Either a warning is not given, or the warning does not give an incorrect reason.

Reproducible with versions: 6000.1.0a4, 6000.0.26f1. 2022.3.52f1, 2021.3.45f1

Not reproducible with versions: - 

Can’t test with versions: - 

Tested on (OS): Windows 10/11

Notes: -