* fix mono HelloWorld sample
Set SelfContained=true. Otherwise we get this when trying to run the
app:
```
./artifacts/bin/H
elloWorld/arm64/Release/osx-arm64/publish/HelloWorld
You must install or update .NET to run this application.
App: /Users/alklig/work/dotnet-runtime/runtime-review/artifacts/bin/HelloWorld/arm64/Release/osx-arm64/publish/HelloWorld
```
* fix samples
<PropertyGroup>
<OutputType>Exe</OutputType>
<TargetFramework>$(NetCoreAppCurrent)</TargetFramework>
+ <!-- always set SelfContained when running to use Mono on desktop -->
+ <SelfContained>true</SelfContained>
</PropertyGroup>
<UsingTask TaskName="MonoAOTCompiler"
<OutputType>Exe</OutputType>
<TargetFramework>$(NetCoreAppCurrent)</TargetFramework>
<EnableDefaultCompileItems>false</EnableDefaultCompileItems>
+ <!-- always set SelfContained when running to use Mono on desktop -->
+ <SelfContained>true</SelfContained>
</PropertyGroup>
<PropertyGroup>