Added missed code in Versions.props

Author: huulinhnguyen-dev

eng/Versions.props

@@ -7,6 +7,10 @@
     <PackageValidationBaselineVersion>17.11.4</PackageValidationBaselineVersion>
     <AssemblyVersion>15.1.0.0</AssemblyVersion>
     <PreReleaseVersionLabel>preview</PreReleaseVersionLabel>
+
+    <!-- differentiate experimental insertions to avoid package id conflicts, 
+    it has to be alphabetically after "preview" to avoid downgrade errors in VS -->
+    <PreReleaseVersionLabel Condition="'$(IsExperimental)' == 'true'">test</PreReleaseVersionLabel>
     <DotNetUseShippingVersions>true</DotNetUseShippingVersions>
     <!-- Workaround for https://github.com/dotnet/roslyn/issues/35793 -->
     <SemanticVersioningV1>true</SemanticVersioningV1>