Use UsingMSBuildSDKSystemWeb property to avoid ASPIRE004 warning.

[CZEMacLeod]

Cleaner way of handing APIRE004 issue instead of supressing the warning.

This sets the property _IsExecutable on projects based on MSBuild.SDK.SystemWeb when calling the GetTargetFrameworksWithPlatformForSingleTargetFramework target.

This target is used in the call to get AdditionalPropertiesFromProject which is then used in the GetNonExecutableReferences task which returns project references which have this set to false.
_ValidateAspireHostProjectResources then triggers the ASPIRE004 warning for each such project.

https://github.com/dotnet/aspire/blob/ad77802ef553c1e146512588ab05d08453d7e381/src/Aspire.Hosting.AppHost/build/Aspire.Hosting.AppHost.in.targets#L115-L183

This does require MSBuild.SDK.SystemWeb >= 4.0.97 but global.json sets version 4.0.104

[twsouthwick]

Thanks! Any thoughts on merging it into the MSBuild.SDK.SystemWeb project?

[twsouthwick]

Just a spelling issue - looks good once that's fixed

[CZEMacLeod]

I have considered this - even just adding the property _IsExecutable globally in the SDK. I'm just not sure what effect that might have elsewhere.
I don't know if the MSBuild task in _ValidateAspireHostProjectResources passes any properties that could be used to detect that the GetTargetFrameworksWithPlatformForSingleTargetFramework was called from an aspire host project.
If so, it would be easier to selectively enable it and I'd be happy to include it in 'MSBuild.SDK.SystemWeb'.