Update Resource utilization health checks doc page

[evgenyfedorov2]

Resource utilization health checks does not require registering Resource Monitoring any more. The issue was dotnet/extensions#4560 and resolved by dotnet/extensions#5413. Now, updating the docs accordingly.

---

Internal previews

📄 File	🔗 Preview link
docs/core/diagnostics/diagnostic-health-checks.md	docs/core/diagnostics/diagnostic-health-checks

[evgenyfedorov2]

@gewarren please review the PR.
OPS status check is failing but I don't think it is related to my changes

[RussKie]

@evgenyfedorov2 I see the deleted parts of the docs but no additions? Should the docs at least talk about the erroneous scenario as you described in dotnet/extensions#5413?

[evgenyfedorov2]

@evgenyfedorov2 I see the deleted parts of the docs but no additions? Should the docs at least talk about the erroneous scenario as you described in dotnet/extensions#5413?

That's because I found that the registration of custom IResourceMonitor implementations is not documented at all, that's why there is no place where to add the erroneous scenario.

@IEvangelist are you aware of any specific reason why it is not documented how to add custom implementations of IResourceMonitor, e.g. .AddSingleton<IResourceMonitor, MyResourceMonitor>()? Adding such a custom implementation would be another workaround preventing the issue dotnet/extensions#4560 from happening, but even if there was not that issue, it might be worth documenting it in general. I mean, default stuff registered by AddResourceMonitoring() might not be enough for some customers and they might want to register their own, but it is not documented at all. What do you think?