AO3-7280 Fix: Posting first chapter now posts the work

[ncunningham9]

Pull Request Checklist

• Have you read "How to write the perfect pull request"?
• Have you read the contributing guidelines?
• 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)
• Do you have fewer than 5 pull requests already open? If not, please wait
  until they are reviewed and merged before creating new pull requests.

Issue

https://otwarchive.atlassian.net/browse/AO3-7280

Purpose

What does this PR do?
Fixes the posting first chapter bug as described in AO3-7280.
The test already existed, so I removed the pending line.

Testing Instructions

How can the Archive's QA team verify that this is working as you intended?
Steps to reproduce
Log in
Post > New Work
Fill in the required fields
Press “Save Draft”
Press “Edit”
Press “Add Chapter”
Fill in some chapter content
Press “Save Draft”
Press “Cancel”
Press “Previous Chapter”
Press “Edit Chapter”
Press “Post”
Press “Entire Work”

If you have a Jira account with access, please update or comment on the issue
with any new or missing testing instructions instead.

I don't have access yet! I'm brand new. My wife wanted to post something on AO3, I poked around in Jira and found this issue. So I thought I'd help with the contribution as a way to say thanks. If I messed up the contribution in any way, feel free to let me know.

Credit

What name and pronouns should we use to credit you in the [Archive of Our Own's Release Notes]

Nathan Cunningham, He/Him

[sarken]

Hi, Nathan Cunningham!

Thank you so much for this pull request. Someone will be along to review it soon.

I've updated the Jira issue status to In Review so no one mistakenly opens a duplicate pull request. If you'd like the ability to comment on, assign, and transition issues in the future, you're welcome to create a Jira account! It makes things a bit easier for us on the organizational side if the Full Name on your Jira account either closely matches the name you'd like us to credit in the release notes or includes it in parentheses, e.g. "Nickname (CREDIT NAME)."

Once you've done that (or if you've already done it -- Jira has been unreliable about showing us new accounts in the admin panel lately), you can either reply here or send an email to otw-coders@transformativeworks.org with your account name and email address and we'll set up the permissions for you.

Thanks again for contributing! If you have any questions, you can contact us at the same email address listed above.