AO3-7606 Replace tag.strong with style_bold

[rosarette]

Pull Request Checklist

• Have you read the contributing guidelines?
• Have you read "How to write the perfect pull request"?
• 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.
• I acknowledge that submitting code created or modified with the help of AI is a bannable offense.

Issue

https://otwarchive.atlassian.net/browse/AO3-7606
I don't have access to the Jira Board yet!

Purpose

What does this PR do?
Changed tag.strong to style_bold in admin_deleted_work_notification.html.erb to match the i18n standard for mailing as requested

Testing Instructions

How can the Archive's QA team verify that this is working as you intended?

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

You can remove this section if there are already full testing instructions in the Jira issue.

Visit http://localhost:3000/rails/mailers, under User Mailer click on admin_deleted_work_notification and check there!

Credit

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

If you have a Jira account, please include the same name in the "Full name"
field on your Jira profile, so we can assign you the issues you're working on.

Please note that if you do not fill in this section, we will use your GitHub account name and
they/them pronouns.

rosarette (she/her) is fine! sorry if i made any mistakes here btw, i havent used git before
My Jira account should be under the same name "rosarette"

[sarken]

Hi, rosarette!

Thank you so much for this pull request. The change looks good to me, so if the tests finish running successfully, I'll mark this approved!

In the meantime, I've updated the Jira issue status to In Review so no one mistakenly creates a duplicate pull request.

Jira has been unreliable about showing us new accounts in the admin panel, and I unfortunately can't find yours to update your permissions. If you could either reply here or send an email to otw-coders@transformativeworks.org with your account's email address, we should be able to fix that and get you set up.

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