runtime: Microsoft.Extensions.Hosting.Systemd.SystemdHelpers.IsSystemdService does not work inside containers.

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

Microsoft.Extensions.Hosting.UseSystemd() is set up to no-op if IsSystemdService() returns false. However, IsSystemdService() only returns true if the direct parent process is systemd. This is not true when we have a container runtime (e.g. podman) acting as a middleman, and thus containerised systemd services do not have sd-notify integration or systemd log formatting.

Expected Behavior

If there exists a more robust check that would work in containerised deployments, then IsSystemdService() should use that.

Otherwise, an overload of UseSystemd() should be created (e.g. UseSystemd(bool forceEnable = false)) that allows users to forcibly enable sd-notify integration and systemd log formatting, without having to manually copy the part of UseSystemd() that is inside the if statement from the reference source into our startup code, since this code may be subject to change in the future.

Steps To Reproduce

Minimalist reproduction here

Exceptions (if any)

No response

.NET Version

6.0.101

Anything else?

.NET SDK (reflecting any global.json):
 Version:   6.0.101
 Commit:    ef49f6213a

Runtime Environment:
 OS Name:     fedora
 OS Version:  35
 OS Platform: Linux
 RID:         fedora.35-x64
 Base Path:   /home/james/.dotnet/sdk/6.0.101/

Host (useful for support):
  Version: 6.0.1
  Commit:  3a25a7f1cc

.NET SDKs installed:
  6.0.101 [/home/james/.dotnet/sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.App 6.0.1 [/home/james/.dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 6.0.1 [/home/james/.dotnet/shared/Microsoft.NETCore.App]

To install additional .NET runtimes or SDKs:
  https://aka.ms/dotnet-download