Cleanup: Remove Unused use_ambient_occusion Property

`use_ambient_occlusion` is a legacy property and not
connected to anything. The clip editor still write
to it for enabling the ambient occlusion renderpass.

This change will remove the legaccy option and
won't enable ambient occlusion pass anymore due
to visual and performance impact.

Pull Request: https://projects.blender.org/blender/blender/pulls/109783

scripts/startup/bl_operators/clip.py

@@ -564,8 +564,7 @@ class CLIP_OT_setup_tracking_scene(Operator):
             world = bpy.data.worlds.new(name="World")
             scene.world = world
 
-        # Having AO enabled is nice for shadow catcher.
-        world.light_settings.use_ambient_occlusion = True
+        # Setup ambient occlusion parameters for convenience.
         world.light_settings.distance = 1.0
         if hasattr(scene, "cycles"):
             world.light_settings.ao_factor = 0.05

source/blender/makesdna/DNA_world_types.h

@@ -97,7 +97,7 @@ enum {
   WO_MODE_UNUSED_3 = 1 << 3, /* cleared */
   WO_MODE_UNUSED_4 = 1 << 4, /* cleared */
   WO_MODE_UNUSED_5 = 1 << 5, /* cleared */
-  WO_AMB_OCC = 1 << 6,
+  WO_MODE_UNUSED_6 = 1 << 6, /* cleared */
   WO_MODE_UNUSED_7 = 1 << 7, /* cleared */
 };
 

source/blender/makesrna/intern/rna_world.cc

@@ -130,14 +130,6 @@ static void rna_def_lighting(BlenderRNA *brna)
   RNA_def_struct_ui_text(srna, "Lighting", "Lighting for a World data-block");
 
   /* ambient occlusion */
-  prop = RNA_def_property(srna, "use_ambient_occlusion", PROP_BOOLEAN, PROP_NONE);
-  RNA_def_property_boolean_sdna(prop, nullptr, "mode", WO_AMB_OCC);
-  RNA_def_property_ui_text(
-      prop,
-      "Use Ambient Occlusion",
-      "Use Ambient Occlusion to add shadowing based on distance between objects");
-  RNA_def_property_update(prop, 0, "rna_World_update");
-
   prop = RNA_def_property(srna, "ao_factor", PROP_FLOAT, PROP_FACTOR);
   RNA_def_property_float_sdna(prop, nullptr, "aoenergy");
   RNA_def_property_range(prop, 0, INT_MAX);