NaN + Hacked Client Dupe

[KhrysAK47]

Describe the bug
A dupe glitch that allows players to get any amount of traded items.

To Reproduce
Steps to reproduce the behavior:

1. Enable Vault trade layout
2. Initiate a trade with someone
3. Set the currency amount to 'NaN'.
4. Use a client with dual trade like Wurst and since NaN breaks trade gui, simply trade what you want.

Expected behavior
It should not happen.

Screenshots
If applicable, add screenshots to help explain your problem.

Additional context
Running latest version of TradeSystem to the date of this report and Paper 1.20.4.

Discord contact: khrystyian

[KhrysAK47]

Bump

[KhrysAK47]

Fixing the ability to put NaN in custom currency should fix this.