feat: Count implicit tags

[bradenmacdonald]

This updates our "get tag counts" API so that the tag counts can include the implicit tags.

Currently, we have an inconsistency in how the counts are displayed in the platform:

This API change will allow us to make the counts in both places include the implicit tags (use the higher number consistently).

Private ref: FAL-3573

[openedx-webhooks]

Thanks for the pull request, @bradenmacdonald! Please note that it may take us up to several weeks or months to complete a review and merge your PR.

Feel free to add as much of the following information to the ticket as you can:

• supporting documentation
• Open edX discussion forum threads
• timeline information ("this must be merged by XX date", and why that is)
• partner information ("this is a course on edx.org")
• any other information that can help Product understand the context for the PR

All technical communication about the code itself will be done via the GitHub pull request interface. As a reminder, our process documentation is here.

Please let us know once your PR is ready for our review and all tests are green.

[yusuf-musleh]

👍 LGTM, works well.

• I tested this: I made sure the tag counts (including implicit) were correct by adding/removing tags
• I read through the code
• I checked for accessibility issues
• Includes documentation
• I made sure any change in configuration variables is reflected in the corresponding client's configuration-secure repository.

[bradenmacdonald]

@ormsbee would you mind reviewing this PR?

[ormsbee]

This is one of those things where I think we should watch the performance numbers closely. And now that we're completely on MySQL 8.0, I suspect we could do more of this in the database with CTE. But that can be a bridge we cross if and when we need to.

[ChrisChV]

@ormsbee Thanks for the review! Could you merge this PR? @bradenmacdonald is on holidays 🙂

[openedx-webhooks]

@bradenmacdonald 🎉 Your pull request was merged! Please take a moment to answer a two question survey so we can improve your experience in the future.