[Bank] Bank transfer logic at max balance

[aikaterna]

Command bugs

Command name

bank transfer

What cog is this command from?

bank

What were you expecting to happen?

For a user to keep their credits after a failed transfer attempt.

What actually happened?

The transfer amount disappeared into the void.

How can we reproduce this issue?

Users A and B both have 60% of max balance amount in their bank. User A gives User B 50% of the max balance amount via the bank transfer command. User B would now at 110% of max balance and the bot replies "User B's balance cannot rise above 9,223,372,036,854,775,807 credits." However, User A will now be at 10% of max balance instead of the expected 60% of max. The transfer amount is being deducted from User A's balance when it shouldn't have been.

[Flame442]

Fixed by #2925