crypto: replace ToECDSAPub with error-checking func UnmarshalPubkey (#16932)

ToECDSAPub was unsafe because it returned a non-nil key with nil X, Y in
case of invalid input. This change replaces ToECDSAPub with
UnmarshalPubkey across the codebase.

internal/ethapi/api.go

@@ -461,13 +461,11 @@ func (s *PrivateAccountAPI) EcRecover(ctx context.Context, data, sig hexutil.Byt
 	}
 	sig[64] -= 27 // Transform yellow paper V from 27/28 to 0/1
 
-	rpk, err := crypto.Ecrecover(signHash(data), sig)
+	rpk, err := crypto.SigToPub(signHash(data), sig)
 	if err != nil {
 		return common.Address{}, err
 	}
-	pubKey := crypto.ToECDSAPub(rpk)
-	recoveredAddr := crypto.PubkeyToAddress(*pubKey)
-	return recoveredAddr, nil
+	return crypto.PubkeyToAddress(*rpk), nil
 }
 
 // SignAndSendTransaction was renamed to SendTransaction. This method is deprecated