Fix ncrunch configuration. (#20437)
When Avalonia updated to `net10.0` it broke the ncrunch configuration. I re-configured everything from scratch here as now we're not targeting `netstandard2.0` by default we only really need to test our current target framework (`net10.0`).
Also made it so that every project was ignored by default and projects that are needed are whitelisted. This should mean that things don't break when new projects are added that are unrelated to things that will be tested.