Port InformationVersion fix to Mono corelib (#60614)

#60572 for Mono's corelib.

Author: akoeplinger

src/mono/System.Private.CoreLib/System.Private.CoreLib.csproj

@@ -32,6 +32,7 @@
     <RuntimeMetadataVersion>v4.0.30319</RuntimeMetadataVersion>
     <!-- Override InformationalVersion during servicing as it's returned via public api. -->
     <InformationalVersion Condition="'$(PreReleaseVersionLabel)' == 'servicing'">$(ProductVersion)</InformationalVersion>
+    <InformationalVersion Condition="'$(StabilizePackageVersion)' == 'true'">$(ProductVersion)</InformationalVersion>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
     <NoWarn>$(NoWarn),0419,0649</NoWarn>
     <Nullable>enable</Nullable>