Use System.Diagnostics.UnreachableException to handle unreachable code paths

.NET 7 introduced System.Diagnostics.UnreachableException that is meant to handle unreachable code paths. https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.unreachableexception?view=net-7.0

Existing exceptions used in such scenarios should be replaced with UnreachableException.

Acceptance Criteria

[ ] Use System.Diagnostics.UnreachableException to handle unreachable code paths

[ ] Automated Tests - new and modified code is covered with automated tests
[ ] Documentation - new and modified APIs are documented
[ ] Performance - performance is verified to avoid regression
[ ] Compatibility - consider compatibility of APIs and functionality with previous version and provide upgrade path if possible
[ ] Demo Application - if new functionality should be showcased in Demo Application or existing functionality changed then update Demo Application
[ ] Release Activities - if release process is affected update Release Activities issue template