PHOAM-022: Wrong event topic can mislead data consumers

[gangov]

Location

./contracts/stake/src/contract.rs:245

Description
The events triggered at the end of the unbond function use the incorrect event topic (bond instead of unbond). Any off-chain system relying on these events could be misled into processing incorrect information, potentially resulting in an overestimation of the number of bonds.

Recommendation
Correct the event topic to accurately reflect the function from which it is triggered (unbond).