[stable14] filter null values for UserManager::getByEmail#11976

rullzer merged 1 commit intostable14nextcloud/server:stable14from

bugfix-stable14/9326/make_sure_usermanager_getByEmail_only_returns_IUsernextcloud/server:bugfix-stable14/9326/make_sure_usermanager_getByEmail_only_returns_IUserCopy head branch name to clipboard