Enable SWC by default when there is no custom Babel config (#29811)
Co-authored-by: Tobias Koppers <tobias.koppers@googlemail.com>
Co-authored-by: jj@jjsweb.site <jj@jjsweb.site>
Co-authored-by: Maia Teegarden <dev@padmaia.rocks>
Co-authored-by: padmaia <padmaia@users.noreply.github.com>