Issue(s) Resolved

Resolves #871

High-level Explanation of PR

An error is thrown in removeAllPubRelationsBySlugs when the array of provided slugs is empty. This PR returns an empty array early in such cases, preventing the error.

Test Plan

1. Delete a single relation using the DELETE /relations endpoint, e.g.

DELETE https://app.pubpub.org/api/v0/c/arcadia-dev/site/pubs/c7e02fdc-e3bf-4422-a5f7-8e112e3b3e8d/relations
Authorization: Bearer <token>
Prefer: "return=representation"
Accept: "*/*"
Content-Type: "application/json",

{
  "arcadia-dev:pub-content-types": [ "0a8b81c9-e025-4e08-94aa-f669630b62f0" ]
}

2. The relation should be deleted with a response status code of 200.

Screenshots (if applicable)

Notes