The value of `key` will always be `!= null` because earlier in the
function, `ERR_CRYPTO_SIGN_KEY_REQUIRED` is thrown if `key` is falsy.
Remove condition that subsequently checks that `key != null`.
PR-URL: https://github.com/nodejs/node/pull/38072
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Darshan Sen <raisinten@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Filip Skokan <panva.ip@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>