fix [#28751] Item in Enum propertie is grayed out

was infact a very old bug where an empty title took the following word for the title, eg: "%t|First Item|Second Item"
the first item would be evaluated as a title.

source/blender/editors/interface/interface_regions.c

@@ -174,7 +174,7 @@ static MenuData *decompose_menu_string(const char *str)
 				*s= '\0';
 				s++;
 			} else if (s[1]=='t') {
-				nitem_is_title= 1;
+				nitem_is_title= (s[2] != '|'); /* check for empty title */
 
 				*s= '\0';
 				s++;

source/blender/python/intern/bpy_props.c

@@ -973,7 +973,7 @@ static EnumPropertyItem *enum_items_from_py(PyObject *seq_fast, PyObject *def, i
 
 			PyErr_Format(PyExc_TypeError,
 			             "EnumProperty(..., default=\'%s\'): not found in enum members",
-			             def);
+			             def_cmp);
 			return NULL;
 		}
 	}