[web/ajax] don't override any status code with 500 in ajax_error_handler
If the request produced an error such as Unauthorized or NotFound,
core_handle sets an appropriate status_out. Which is then overridden by
the ajax error handler.
drop_relation_definition('CWSourceSchemaConfig', 'cw_schema', 'CWAttribute')
sync_schema_props_perms('cw_schema')