UI: Correct icon and description for "Object Line Art"

The icon should be the same as other object icons rather than "Cube",
and the description was just the collection description copy and pasted.

source/blender/makesrna/intern/rna_object.c

@@ -172,9 +172,9 @@ const EnumPropertyItem rna_enum_object_gpencil_type_items[] = {
      "Quickly set up Line Art for active collection"},
     {GP_LRT_OBJECT,
      "LRT_OBJECT",
-     ICON_CUBE,
+     ICON_OBJECT_DATA,
      "Object Line Art",
-     "Quickly set up Line Art for active collection"},
+     "Quickly set up Line Art for the active object"},
     {0, NULL, 0, NULL, NULL}};
 
 static const EnumPropertyItem parent_type_items[] = {