The Conversion --> Import task pipeline sometimes fails, but editors don't know why

[goose-life]

There are a few places it can go wrong. Let's map out the ideal process, and add a comment on the Conversion task at each point of the workflow if it doesn't go as planned.

Examples of how things can go wrong:

• no related import task is found
• the user doing the Conversion task doesn't have the right permissions
• the import fails
• the dates don't match