fix(node/crypto): Assign publicKey and privateKey with let instead of…

… const (#24943)

Because public/private key are reassigned, they should be `let` instead
of `const`.

Co-authored-by: Divy Srivastava <dj.srivastava23@gmail.com>

ext/node/polyfills/internal/crypto/keygen.ts

@@ -573,8 +573,8 @@ export function generateKeyPair(
     const privateKeyHandle = op_node_get_private_key_from_pair(pair);
     const publicKeyHandle = op_node_get_public_key_from_pair(pair);
 
-    const privateKey = new PrivateKeyObject(privateKeyHandle);
-    const publicKey = new PublicKeyObject(publicKeyHandle);
+    let privateKey = new PrivateKeyObject(privateKeyHandle);
+    let publicKey = new PublicKeyObject(publicKeyHandle);
 
     if (typeof options === "object" && options !== null) {
       const { publicKeyEncoding, privateKeyEncoding } = options as any;