Fix #137493: UI: Show "Active Spline" panel for surface types

Previously in 5fe1051839 the "Active
Spline" panel was moved to the viewport but not updated correctly for it
to display when active object is of "SURFACE" type. Now it will show for
both curve and surface types.

scripts/startup/bl_ui/space_view3d.py

@@ -8132,7 +8132,7 @@ class VIEW3D_PT_active_spline(Panel):
     @classmethod
     def poll(cls, context):
         ob = context.object
-        if ob is None or ob.type != 'CURVE' or ob.mode != 'EDIT':
+        if ob is None or ob.type not in {'CURVE', 'SURFACE'} or ob.mode != 'EDIT':
             return False
         curve = ob.data
         return curve.splines.active is not None