Merge the two into a single progress message

[DonJayamanne]

I think we should merge these two into single progress message.
Using VS Code API its possible to update the progress messages, hence displaying two isn't necessary.

Also looks weird to have two.
When the second progress (displayed on top) is just a different stage in the creation..
In which case we can use the progress API to update the progress message

[eleanorjboyd]

great point yes! When creating an environment and installing packages as part of that flow, we should only have one progress which gets updated as the different steps are happening.