Remove inline scripts from import pages.

What does this MR do?

Removes inline scripts from the Import Status pages for all the importers we have.

Are there points in the code the reviewer needs to double check?

That this doesn't break anything (it didn't when I tested it!)

Why was this MR needed?

Inline scripts are bad, this removes a few of them.

What are the relevant issue numbers?

#18231 (closed) and #19866 (closed)

Does this MR meet the acceptance criteria?

• CHANGELOG entry added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the style guides
• Branch has no merge conflicts with master (if you do - rebase it please)
• Squashed related commits together