gui: bugfix, getAvailableBalance skips selected coins

The previous behavior for getAvailableBalance when coin control
has selected coins was to return the sum of them. Instead, we
are currently returning the wallet's available total balance minus
the selected coins total amount.

This turns into a GUI-only issue for the "use available balance"
button when the user manually select coins in the send screen.

Reason:
We missed to update the GetAvailableBalance function to include
the coin control selected coins on #25685.

Context:
Since #25685 we skip the selected coins inside `AvailableCoins`,
the reason is that there is no need to traverse the wallet's
txes map just to get coins that can directly be fetched by
their id.

0 files changed, 0 insertions, 0 deletions