create relations for existing discussions

[gabestein]

Issue(s) Resolved

If a pub (or pub-discussion relationship) was deleted, the gdrive action would fail to create relationships between the pub and existing discussions.

High-level Explanation of PR

If a discussion already exists, it tries to create a new relation for it via the upsert function. We could make this a tiny bit more efficient by checking for the existence of a relationship already and not passing it in, but as the upsert function already does this, seems fine for now.

Test Plan

1. Delete a pub that has some discussions
2. Delete a discussion
3. Re-run the google drive action
4. All discussions should appear as related to the pub, once
5. No duplicate discussions should be created

Screenshots (if applicable)

Notes