AO3-6872 Only notify creators when a work is added to a collection by an archivist

[marcus8448]

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• Have you added tests for any changed functionality?
• Have you added the Jira issue number
  as the first thing in your pull request title (e.g. AO3-1234 Fix thing)
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Issue

https://otwarchive.atlassian.net/browse/AO3-6872

Purpose

Skips the attempt to notify creators when an archivist adds a non-work (a bookmark) to a collection.
Also adds a test to verify that a notification is still sent when a work is added to a collection by an archivist.

Testing Instructions

See instructions on the Jira issue.

References

N/A

Credit

marcus8448 (he/him)

[Bilka2]

Thank you for contributing! Someone will be along to take care of Jira access soon if you've made an account.

In the meantime, I have a review comment: Could you create a test that makes sure that when an archivist adds a bookmark to a collection, there is no error like the one described on Jira and the bookmark is added to the collection?

[Bilka2]

Could you add a check for the email subject or text to make sure it's the right email?

[redsummernight]

FYI looks like #5023 is adding the same test for this mailer. Let's get that one merged first.

[marcus8448]

I've removed the test (as it is slightly tangential to the bug being fixed). If necessary, I can append a check for the email recipient and body to the test in #5023 after it is merged.

[Bilka2]

Thank you!