Currently, users do not see categories at all on the Import Page, except when they open the wikitext.
We should allow users to see which categories their file currently has, and encourage them to exchange them for ones that fit the commons categories.
- There is a category box below the displayed wikitext on FileInfo as shown in the mock
- Below the category box there is an info text: Files on Wikimedia Commons should be categorized. This makes it easier to find them. You can add categories to this file by editing the file info on this page.
- The category box behaves like it would on a normal Commons page, i.e. it shows all categories that do not exist red linked, and all those that do exist blue linked
- The category info is updated whenever the wikitext was updated
The edge case of no categories existing for the file will be treated in a different ticket.
Thoughts so far:  If there is no category yet, it adds and shows the "Media needing category" category for Commons, but allows any other category to be added in general
UploadWizard is dealing with this in a way we could copy.