fix(gatsby): with some custom babel configs array spreading with Set is not safe

[pieh]

Description

With some custom .babelrc configs those can result in wrong transpiled code:

  var deduplicatedErrors = react__WEBPACK_IMPORTED_MODULE_6__.useMemo(function () {
    return [].concat(new Set(errors));
  }, [errors]);

Array.from does same thing without above:

  var deduplicatedErrors = react__WEBPACK_IMPORTED_MODULE_6__.useMemo(function () {
    return Array.from(new Set(errors));
  }, [errors]);

[vladar]

Thank you 🙏