Fix change tracking and failed edit state handling

[jscarle]

Summary

• fix change-tracking so tracked child objects and field type edits are actually cleared after successful operations
• keep items and templates dirty when CreateItem(...) or EditItem(...) fail instead of marking them clean prematurely
• add regression coverage for the change-tracking and failure paths, and document that skipped live tests in this repo are typically due to test-account capability limits

Testing

• dotnet build OnePassword.NET.sln -c Release
• dotnet test OnePassword.NET.sln -c Release