Show issue assignment in summary panel

[NateWr]

Describe the problem you would like to solve
Editors want to be able to see if a submission is assigned to an issue, and which issue, without leaving the submissions list, so that they can manage many submissions more quickly.

Describe the solution you'd like
Add this information to the submission summary panel. If a submission is not assigned to an issue, allow someone to assign the issue to a submission from this panel.

Who is asking for this feature?
This was a recommendation after user tests for #7495.

Additional information
The following mockups show what this could look like in the summary panel (bottom right).