Fix: Simplify import in VR add-on

In the Viewport VR Preview, an unusual and complicated import
manipulates sys.path to import a class from a file that is already
importable anyway.

There is no documented reason for this, and the common way to subclass an RNA type in python is by using its `bpy.types....` registered class, _not_ by directly subclassing the python type used to declare/register the parent type.

Pull Request: https://projects.blender.org/blender/blender/pulls/147656

scripts/addons_core/viewport_vr_preview/gui.py

@@ -18,11 +18,7 @@ from bpy.types import (
     Panel,
     UIList,
 )
-# Add space_view3d.py to module search path for VIEW3D_PT_object_type_visibility import.
-import os.path
-import sys
-sys.path.append(os.path.abspath(os.path.join(os.path.dirname(__file__), '../../startup/bl_ui')))
-from space_view3d import VIEW3D_PT_object_type_visibility
+from bpy.types import VIEW3D_PT_object_type_visibility
 
 
 # Session.