`AccountTransaction::handle_fee` should not take `&self` as arg

[tdelabro]

    fn handle_fee(
        &self,
        state: &mut dyn State,
        tx_context: Arc<TransactionContext>,
        actual_fee: Fee,
        charge_fee: bool,
    ) -> TransactionExecutionResult<Option<CallInfo>> {
        if !charge_fee || actual_fee == Fee(0) {
            // Fee charging is not enforced in some transaction simulations and tests.
            return Ok(None);
        }

        // Charge fee.
        let fee_transfer_call_info = Self::execute_fee_transfer(state, tx_context, actual_fee)?;

        Ok(Some(fee_transfer_call_info))
    }

&self is not used. It can be removed and implemented as a type function, like Self::execute_fee_transfer it internally calls.
Or even as a standalone function as it does not use anything associated with the type like type constants or anything else

[Subsegment]

I want to make some contribution to the repo. Please assign it to me:)