Bring back properties until we re-bootstrap to a newer Arcade SDK (#15330)

Author: ViktorHofer

Directory.Build.props

@@ -16,6 +16,11 @@
     <RepositoryUrl>https://github.com/dotnet/arcade</RepositoryUrl>
     <!-- Only upgrade NuGetAudit warnings to errors for official builds. -->
     <WarningsNotAsErrors Condition="'$(OfficialBuild)' != 'true'">$(WarningsNotAsErrors);NU1901;NU1902;NU1903;NU1904</WarningsNotAsErrors>
+    <!-- TODO: Remove when the VMR uses a new bootstrap Arcade.Sdk in source-only builds that has the TFM changes in TargetFrameworkDefaults.props. -->
+    <NetCurrent>net10.0</NetCurrent>
+    <NetPrevious>net9.0</NetPrevious>
+    <NetToolCurrent>$(NetCurrent)</NetToolCurrent>
+    <NetToolMinimum Condition="'$(DotNetBuildSourceOnly)' == 'true'">$(NetToolCurrent)</NetToolMinimum>
   </PropertyGroup>
 
 </Project>