Fix: Allow table rendering in markdown preview tool

[MaoShizhong]

Because

Some of our lessons have markdown tables but the necessary table tags (table/thead/tbody/tr/th/td) are not included in rails-html-sanitizer's default allowed tags, meaning our markdown preview tool won't render tables.

This PR

• Adds table/thead/tboyd/tr/th/td tags to Markdown::PreviewComponent#allowed_tags.

Issue

N/A

Additional Information

For QA

Go to the markdown preview tool and enter

| Verb   | Action | Example                                       |
| ------ | ------ | --------------------------------------------- |
| POST   | Create | `POST /posts` Creates a new blog post         |
| GET    | Read   | `GET /posts/:postid` Fetches a single post    |
| PUT    | Update | `PUT /posts/:postid` Updates a single post    |
| DELETE | Delete | `DELETE /posts/:postid` Deletes a single post |

Which will fail to render the table (which renders properly in the actual lessons):

Compare that to when the 6 relevant tags are whitelisted in #allowed_tags, which allows rendering of markdown tables as expected as below:

Pull Request Requirements

• I have thoroughly read and understand The Odin Project Contributing Guide
• The title of this PR follows the keyword: brief description of change format, using one of the following keywords:
  • Feature - adds new or amends existing user-facing behavior
  • Chore - changes that have no user-facing value, refactors, dependency bumps, etc
  • Fix - bug fixes
• The Because section summarizes the reason for this PR
• The This PR section has a bullet point list describing the changes in this PR
• I have verified all tests and linters pass after making these changes.
• If this PR addresses an open issue, it is linked in the Issue section
• If applicable, this PR includes new or updated automated tests

[KevinMulhern]

Nice! 🤌

Thanks @MaoShizhong

[MaoShizhong]

Can't merge this myself anymore :P

[KevinMulhern]

Sorry, forgot myself 😢