Always show all search tabs

If you run a search that returns no Government results, or no government
results with the current organisation filter, the tab would be hidden.

This is problematic for several reasons:
* if you were filtering down results in the government tab, it's suddenly
  disappeared. If you want to change the organisation filter, you can't.
* it appears that there are no results, even though there may be, if there was
  no organisation set. You can't see that you're filtering to an organisation,
  nor which organisation it is.