Saving a Space does not change pathname

The update when saving a space happens in the redux store, but `pathname` is not updated at this moment. We might have path `space/7slvq0` even after saving it.

This is a problem when we want to go back from another path, we lose the `saved` information and `SpaceHeader` will display the unsaved buttons.

This bug happens when export a space with selection.

### To reproduce:
- visit space `7slvq0`
- save space
- export space (with whatever options)

The space header displays the save button.

Reproduce the issue by saving space 7slvq0 and exporting it with a selection, then inspect the Redux state, pathname handling, and SpaceHeader behavior. Done means the pathname reflects the saved state after export and returning to the space shows the saved buttons instead of the save button.

Written by the indexing model from the issue text.