`net_amount` is 0 in pot donation transaction result

[Sliman4]

Describe the bug
net_amount field in pot donation return value is always "0"

To Reproduce
Steps to reproduce the behavior:

1. Make a donation to any pot.
2. Go to https://nearblocks.io/txns/mGdDKMFHj7omhumVA8exQEvSZSjZNCDud7eBprVR87c?tab=execution
3. See "net_amount": "0" under "Result" field.

Expected behavior
"net_amount": "90990000000000000000000", the same value as stored in the contract state