message: Remove unnecessary cast in CKey::SignSchnorr
diff: @@ -288,7 +288,7 @@ bool CKey::SignSchnorr(const uint256& hash, Span<unsigned char> sig, const uint2
  uint256 tweak = XOnlyPubKey(pubkey_bytes).ComputeTapTweakHash(merkle_root->IsNull() ? nullptr : merkle_root);
  if (!secp256k1_keypair_xonly_tweak_add(GetVerifyContext(), &keypair, tweak.data())) return false;
  }
  - bool ret = secp256k1_schnorrsig_sign(secp256k1_context_sign, sig.data(), hash.data(), &keypair, (unsigned char*)aux.data());
  + bool ret = secp256k1_schnorrsig_sign(secp256k1_context_sign, sig.data(), hash.data(), &keypair, aux.data());
  if (ret) {
  // Additional verification step to prevent using a potentially corrupted signature
  secp256k1_xonly_pubkey pubkey_verify;
  