Timeline display bug when user is removed from org

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Describe the bug

If a user creates a note and then that user is removed from the org, the timelines page is unable to display their name. In this case, I added a user, added two notes with that account, and then removed them from the org.

Expected Behavior

SEED should either show the name as blank (or something to that effect), or look up the user regardless of whether they're an org member or not. Though in that case, it might be better to do that lookup in Django, not in the frontend (as it currently does).

Steps to Reproduce

1. Add a user to an organization
2. Create a note on a property, confirm that it creates a note event in the timeline
3. Remove the user from the organization
4. Go to the property's timeline

Instance Information

Tried on the dev2 server.

Additional Context

I haven't checked if this is an issue for other event types, like analyses, but it could be.