[server] fix anonymous_user predicate in tests
devtools' TestServerConfiguration overrides the anonymous_user method,
but not the anonymous-user config option, so testing for the latter
would give the wrong result. Closes #3996664.
fromcubicweb.schemas.baseimportin_group,CWSourceSchemaConfig# copy __permissions__ to avoid modifying a shared dictionaryin_group.__permissions__=in_group.__permissions__.copy()in_group.__permissions__['read']=('managers',)cw_for_source=CWSourceSchemaConfig.get_relation('cw_for_source')cw_for_source.__permissions__={'read':('managers','users'),'add':('managers',),'delete':('managers',)}