GetUnicode_Invalid/GetAscii_Invalid test failures on Fedora 40

Some System.Globalization.Extensions.Tests tests are failing on Fedora 40.
Fedora 40 has libicu 74.2-1.

- `GetUnicode_Invalid`: 158 out of 5421 failed
- `GetAscii_Invalid`: 158 out of 5448 failed

See [testResults.xml.txt](https://github.com/dotnet/runtime/files/14758812/testResults.xml.txt)

cc @tarekgh @omajid 