Fix EditorObjectSelection opening of TrackManager

Calling `Close()` on a window deletes its object, rendering any future
uses of its members invalid.

In this case `WindowsCloseAll` closed Editor window itself rendering
call to `ManageTracks` on a deleted pointer. Previously
`WindowsCloseAll` was called, but earlier in the same function we have
already closed all windows but Editor itself. It is sufficient to close
the editor once we have opened `TrackDesignList`.

When this got fixed, I noticed `TrackDesignList` could not locate any
rides, which was happening due to calls to `ObjectManager::UnloadAll`
in several places. Code to load the selected ride back was added.

src/openrct2-ui/windows/EditorObjectSelection.cpp

@@ -599,12 +599,14 @@ public:
             if (!objectSelectResult.Successful)
                 return;
 
-            // Close any other open windows such as options/colour schemes to prevent a crash.
-            WindowCloseAll();
-            // WindowClose(*w);
+            auto& objRepository = OpenRCT2::GetContext()->GetObjectRepository();
+            _loadedObject = objRepository.LoadObject(listItem->repositoryItem);
+            auto& objManager = OpenRCT2::GetContext()->GetObjectManager();
+            objManager.LoadObject(_loadedObject.get()->GetIdentifier());
 
             // This function calls window_track_list_open
             ManageTracks();
+            Close();
             return;
         }