Resolve "fix(viz): Issues with VTK meshes in SightViewer: zooming and hiding"

Description

1. fix the random crash when the camera is not reset because of some uninitialized variables
2. reset the camera when a model is loaded in SightViewer
3. enable the hide/show model when a model is loaded
4. do not enable the hide/show model when an image is loaded

Closes #866 (closed)

How to test it?

1. You need to set autoresetCamera of modeSeriesAdp in OgreGenericScene.xml back to "false" and then load a mesh.
2. Load a model and observe the camera is reset
3. Load a model and observe the hide/show button is enabled and functional
4. Load a model (without loading an image first) and observe the image buttons are not enabled