[BUG] Error sending the whole balance displayed on webwallet.hydrachain.org

[nenantonov]

Description:
When trying to send the whole HYDRA balance displayed on webwallet.hydrachain.org, the transaction fails with message You do not have enough HYDRA to send.

Test performed to demo the bug:
The test is performed with webwallet.hydrachain.org (from production).

To monitor the available UTXOs a desktop staking wallet (the staking wallet with GUI) is installend on AWS. The purpose is just to be able to easily view the available UXTOs before and after each transaction. The same address as the address used for the webwallet is imported in the staking wallet. There are no immature UTXOs. The staking wallet is not staking. The UTXO set before the send is the following (8 + 0.08485421):

A "send" with the displayed HYDRA balance (8.08485421 HYDRA) is attempted. The transaction is not going through and the error message pops up: You do not have enough HYDRA to send.

Expected behaviour:
It shoule be possible to send the whole balance displayed on the webwallet, after the gas fee is deducted from the balance and the rest is sent.