Make sure platform is correct for packaging env

When archiving the environments, we get the platform from the conda
environment, so we need it to be the correct platform. This only
currently applies when building for osx-64 an a osx-arm64 machine.

Author: jclarkeSTFC

buildconfig/Jenkins/Conda/mamba-utils

@@ -20,7 +20,7 @@ setup_mamba () {
   source $install_prefix/etc/profile.d/mamba.sh
 
   if [ -n "$env_name" ]; then
-    create_and_activate_env "$env_name"
+    create_and_activate_env "$env_name" "$platform"
   fi
 }