[GUI] ScenarioChecker messages should refer to scenario errors instead of topography errors

The topography is only one component that is checked by the ScenarioChecker.

However, each error message contains There are errors in the topography, even if the error is in the Tab Model or Simulation.

The information about the tab (topography, simulation, model) is still displayed. I have not changed anything here..

I have replaced Topography error by Scenario error.