UI: Move Mark/Clear asset out of ID Data in Outliner context menu

They are now always shown in the top-level of the Outliner context menu.
Having them in the ID Data submenu was just a hassle to work with, and
often confusing to users - even if technically correct (the asset status
is part of the ID data).

Part of T82680.

release/scripts/startup/bl_ui/space_outliner.py

@@ -105,6 +105,10 @@ class OUTLINER_MT_context_menu(Menu):
 
     @staticmethod
     def draw_common_operators(layout):
+        layout.menu_contents("OUTLINER_MT_asset")
+
+        layout.separator()
+
         layout.menu("OUTLINER_MT_context_menu_view")
 
         layout.separator()
@@ -306,6 +310,22 @@ class OUTLINER_MT_object(Menu):
         OUTLINER_MT_context_menu.draw_common_operators(layout)
 
 
+class OUTLINER_MT_asset(Menu):
+    bl_label = "Assets"
+
+    @classmethod
+    def poll(cls, context):
+        return context.preferences.experimental.use_asset_browser
+
+    def draw(self, context):
+        layout = self.layout
+
+        space = context.space_data
+
+        layout.operator("asset.mark")
+        layout.operator("asset.clear")
+
+
 class OUTLINER_PT_filter(Panel):
     bl_space_type = 'OUTLINER'
     bl_region_type = 'HEADER'
@@ -451,6 +471,7 @@ classes = (
     OUTLINER_MT_collection_visibility,
     OUTLINER_MT_collection_view_layer,
     OUTLINER_MT_object,
+    OUTLINER_MT_asset,
     OUTLINER_MT_context_menu,
     OUTLINER_MT_context_menu_view,
     OUTLINER_PT_filter,

source/blender/editors/space_outliner/outliner_tools.c

@@ -1747,8 +1747,6 @@ typedef enum eOutlinerIdOpTypes {
   OUTLINER_IDOP_INVALID = 0,
 
   OUTLINER_IDOP_UNLINK,
-  OUTLINER_IDOP_MARK_ASSET,
-  OUTLINER_IDOP_CLEAR_ASSET,
   OUTLINER_IDOP_LOCAL,
   OUTLINER_IDOP_OVERRIDE_LIBRARY_CREATE,
   OUTLINER_IDOP_OVERRIDE_LIBRARY_CREATE_HIERARCHY,
@@ -1775,8 +1773,6 @@ typedef enum eOutlinerIdOpTypes {
 /* TODO: implement support for changing the ID-block used. */
 static const EnumPropertyItem prop_id_op_types[] = {
     {OUTLINER_IDOP_UNLINK, "UNLINK", 0, "Unlink", ""},
-    {OUTLINER_IDOP_MARK_ASSET, "MARK_ASSET", 0, "Mark Asset", ""},
-    {OUTLINER_IDOP_CLEAR_ASSET, "CLEAR_ASSET", 0, "Clear Asset", ""},
     {OUTLINER_IDOP_LOCAL, "LOCAL", 0, "Make Local", ""},
     {OUTLINER_IDOP_SINGLE, "SINGLE", 0, "Make Single User", ""},
     {OUTLINER_IDOP_DELETE, "DELETE", ICON_X, "Delete", ""},
@@ -1859,9 +1855,6 @@ static bool outliner_id_operation_item_poll(bContext *C,
   }
 
   switch (enum_value) {
-    case OUTLINER_IDOP_MARK_ASSET:
-    case OUTLINER_IDOP_CLEAR_ASSET:
-      return U.experimental.use_asset_browser;
     case OUTLINER_IDOP_OVERRIDE_LIBRARY_CREATE:
       if (ID_IS_OVERRIDABLE_LIBRARY(tselem->id)) {
         return true;
@@ -2016,14 +2009,6 @@ static int outliner_id_operation_exec(bContext *C, wmOperator *op)
       }
       break;
     }
-    case OUTLINER_IDOP_MARK_ASSET: {
-      WM_operator_name_call(C, "ASSET_OT_mark", WM_OP_EXEC_DEFAULT, NULL);
-      break;
-    }
-    case OUTLINER_IDOP_CLEAR_ASSET: {
-      WM_operator_name_call(C, "ASSET_OT_clear", WM_OP_EXEC_DEFAULT, NULL);
-      break;
-    }
     case OUTLINER_IDOP_LOCAL: {
       /* make local */
       outliner_do_libdata_operation(