Fixes RigsOfRods#3216 - Airplane dashboard not reacting to mouse

_problem: _
wrong viewport dimensions used when calculating relative mouse position to query for overlay element.
Broken in RigsOfRods#3184. Before that, we queried both mouse position and viewport dimensions directly from OIS.
I had to change that because of OIS bug, and now the dimension values are not updated correctly.

_solution:_
Minimum viable fix - just keep the same dummy OIS event, just update the viewport dimensions.

source/main/utils/InputEngine.cpp

@@ -609,6 +609,10 @@ OIS::MouseState InputEngine::getMouseState()
     // See commentary in `resetKeysAndMouseButtons()`
     // To work around, we keep internal button states and pay attention not to get them polluted by OIS.
     // -----------------------------------------------------------------------------------------------------
+
+    mouseState.width = (int)App::GetAppContext()->GetRenderWindow()->getWidth();
+    mouseState.height = (int)App::GetAppContext()->GetRenderWindow()->getHeight();
+
     return mouseState;
 }