Deleting a peron who has been linked to a survey, breaks the survey submission list

[katjam]

Description

When a person is linked to as survey as a respondent and is subsequently deleted, they remain linked to the survey. This breaks the submission list view for that survey.

Steps to reproduce

1. Go to a survey submission list e.g /organize/1/projects/standalone/surveys/1/submissions
2. Identify a person who has been linked to a survey that you are happy to delete (or make a new one & link them)
3. Go to manage that linked person e.g. /organize/1/people/200/manage and click the Remove person button
4. Return to the submissions list and see the person is still linked with their name visible & a broken avatar image
5. Hover over the avatar to see the crash!

Expected Behaviour (Needs to be defined)

Need to decide if we revert deleted person links to anonymous or if we want to retain any of the info in the respondent data. If we want to retain some of the info, we should make sure the hover does not rely on the person existing.

Actual Behaviour

The name is retained as text.
The hover breaks on trying to fetch person (and their tags)

Screenshots (if you have any)