feat: enhance PredepositGuardian with events, errors, fix bugs

[DiRaiks]

A short summary of the changes.

Context

Event Logging Enhancements:

• Added several new events to log important actions such as topping up node operator bonds, withdrawing bonds, setting vouchers, and validator-related actions.

Error Handling Improvements:

• Updated error messages to include more context, such as the specific validator public key and bond status, to aid in debugging and clarity.

Function Refactoring:

• Refactored the internal _topUpNodeOperatorCollateral function to include additional validation and emit an event upon successful execution.
• Modified the withdrawNodeOperatorBond and setNodeOperatorVoucher functions to emit appropriate events after executing their core logic. [1] [2]

Validation and Withdrawal Logic:

• Enhanced the validation logic in functions like proveValidatorWC and withdrawDisprovenValidator to include more detailed error messages and emit corresponding events. [1] [2]

Miscellaneous:

• Removed unnecessary payable modifiers from certain functions to streamline their functionality.…idation improvements

Potential problem

• Fixed a bug in the logic of the setNodeOperatorVoucher function. The value in memory was reset to zero and the zero value was subsequently used to transfer funds [1]

[Jeday]

Just use msg.value for event

[Jeday]

and state