Stats: Displaying stats as #{id} (loading title)

#### Steps to reproduce the issue

This is a hard one to reproduce and seems to come up for a few reasons. A lot of it with examples can be found on this internal post p2EDhh-wW-p2

One common time seems to be with Woocommerce and product category pages where the ID of the category is thought to be a single page or post and this causes the odd looking stat line. This doesn't happen with all themes though but seems to with [Tortuga](https://wordpress.com/theme/tortuga), [Illustratr](https://wordpress.com/theme/illustratr), and [Maisha](https://wordpress.com/theme/maisha).

1. Setup a site with one of those themes
2. Install WooCommerce
3. Visit one of the product category pages
4. See the stats displaying as #{product_category_id} (loading title)
5. Can not link to item

Another example seems to be with deleted content. I've seen at least one example of an attachment page being viewed, then the media item being deleted and the media id showing in the posts and pages section of stats with the same format #{media_id} (loading title)

#### What I expected

This shouldn't show up in the posts and pages section of the stats as they are really archive type pages.
Maybe have a section of Misc page views or have them count in the Homepage / Archives section of the stats.

#### What happened instead

The odd stat description shows in the Post and pages section of stats and causes confusion.

Start by reproducing the issue with WooCommerce and the Tortuga, Illustratr, or Maisha themes, then compare the affected product-category and deleted-media cases. Use the linked internal post for additional examples; done means these archive or deleted-content views no longer appear as #{id} loading titles in the Posts and Pages stats section.

Written by the indexing model from the issue text.