[PBNTR-242] Hotfix: Remove advanced_table_example_mock_data.rb (#3318)

**What does this PR do?** A clear and concise description with your
runway ticket url.

`advanced_table_example_mock_data.rb` is causing the site to crash
repeatedly. The file isn't being used and is not a module, so Zeitwerk
fails to autoload it.


<img width="1680" alt="Screenshot 2024-04-01 at 11 50 21 AM"
src="https://github.com/powerhome/playbook/assets/2293844/dd9f7955-dcf6-4e17-8c28-1868e6cccd1f">



#### Checklist:
- [x] **LABELS** Add a label: `enhancement`, `bug`, `improvement`, `new
kit`, `deprecated`, or `breaking`. See [Changelog &
Labels](https://github.com/powerhome/playbook/wiki/Changelog-&-Labels)
for details.
- [x] **DEPLOY** I have added the `milano` label to show I'm ready for a
review.
- [ ] **TESTS** I have added test coverage to my code.