Update email copy for confirmation email once a list has finished processing

[hlennett]

Overview

We had spotted some hyperlinks missing from the current copy in the email that is sent to users when their list finishes processing and took it as an opportunity to make some updates to the email copy as a whole.

Is your feature request related to a problem? Please describe.

Replace current email copy sent when a list finishes processing with this more robust text.

Describe the solution you'd like

Please use the copy in this document: https://docs.google.com/document/d/1_1jP8NURMiRyjFRnBUfi3r8XbsIb0vPXYWtS1IM_rms/edit?usp=sharing

Additional Context

cc @katieashaw

Could be completed with #1439 and #1438