Fix for broken import pages widget #62907036

Per [story 62907036](https://www.pivotaltracker.com/story/show/62907036) and due to [PR 795](https://github.com/reciprocity/ggrc-core/pull/795).  Inner nav section on import interface was not rendering the widget in cases where there were no other objects to show.

This removes some undesirable `.hide()` actions and explicitly re-`show()`s widgets in some edge cases that were introduced by the above PR.