v9: some url paths are not correct on case sensitive filesystems

[Zeegaan]

Fixes: #11670

Notes

• recase assignDomain to assigndomain

How to test

• If you're on Windows, navigate to your umbraco folder and run the powershell script (Get-ChildItem -Recurse -Directory).FullName | ForEach-Object {fsutil.exe file setCaseSensitiveInfo $_ enable}
• Run umbraco
• Create an empty document type and allow as root
• Create a content page for the document type
• Right click the content and click "Culture and Hostnames" this should now give you a menu and not an error

[nikolajlauridsen]

LGTM and tests out great as well 🎉