Allow for importing own shared history

[ElectronicBlueberry]

When a history is made publicly accessible via link, the user who created it can not import it.

This can lead to the publishing user being unsure if the history is importable, and can make it harder to demonstrate this step in trainings.

It would be nice if we could always display the import button, and move the "switch to this history" button somewhere else. Maybe add a banner which reads: "You published this history" with the switch to history button next to it.