Fix filename string replace

Author: pjcollins

build-tools/create-packs/Directory.Build.targets

@@ -80,7 +80,7 @@
     />
     <Unzip
         SourceFiles="@(_WLPacks)"
-        DestinationFolder="$(DotNetPreviewPath)packs\$([System.String]::Copy('%(_WLPacks.Filename)').Replace('$(AndroidPackVersionLong)', ''))\$(AndroidPackVersionLong)"
+        DestinationFolder="$(DotNetPreviewPath)packs\$([System.String]::Copy('%(_WLPacks.Filename)').Replace('.$(AndroidPackVersionLong)', ''))\$(AndroidPackVersionLong)"
     />
     <Touch
         Files="$(DotNetPreviewPath)sdk\$(DotNetPreviewVersionFull)\EnableWorkloadResolver.sentinel"