Additional Tests to reinforce API filtering for Preprints [OSF-7418]

[erinspace]

Purpose

There was some question previously about being able to get all "types" of preprints using the API preprint filter.

The general understanding was that Preprints can be in a few states (from the linked Jira ticket)

1. Valid - has a published preprint with a non-orphaned file
2. Orphaned - has a published preprint with an orphaned file
3. Abandoned - has a non-published preprint, file status irrelevant
4. None - Has no preprints of any kind associated

2, 3, and 4 should be included when ?filter[preprint]=false, 1 for true

This PR adds a few tests that better ensure that these conditions are met, specifically for double checking orphaned and abandoned preprints

Changes

• tests to check that orphaned preprints appear in filter[preprint]=False and NOT in filter[preprint]=True
• tests to check that un-pubublished (abandoned) preprints appear in filter[preprint]=False and NOT in filter[preprint]=True

Side effects

None

Notes!

I think some of the confusion on the Jira ticket revolved around API behavior when the PreprintService is deleted, what happens to the Node that corresponds? I do believe this ticket in general was for the preprint filter, in the above states, and not with Node - PreprintService object relationships.

Ticket

https://openscience.atlassian.net/browse/OSF-7418