[Minor] Workaround NuGet SourceRoots issue no longer needed?

[jeroenhabets]

I noticed:

Microsoft.IO.RecyclableMemoryStream/src/Microsoft.IO.RecyclableMemoryStream.csproj

Lines 55 to 61 in e6db6fa

	<!-- Workaround for https://github.com/dotnet/sdk/issues/11105 -->
	<ItemGroup>
	<SourceRoot Include="$(NuGetPackageRoot)\" Condition="'$(NuGetPackageRoot)' != ''" />
	</ItemGroup>
	<ItemGroup>
	<EditorConfigFiles Remove=".editorconfig" />
	</ItemGroup>

but dotnet/sdk#11105 and all follow up issues NuGet/Home#9431 and NuGet/Home#9810 have been fixed and Closed more than five years ago, so I suspect this workaround is no longer needed?