Linter: Unprotected terminate_contract

[jubnzv]

The terminate_contract function call must be protected with access controls that check the address of the caller. This is necessary to avoid destructing the contract by malicious third-parties.

Examples:

#[ink(message)]
pub fn bad(&mut self) -> Result<()> {
    self.env().terminate_contract(self.sender); // Error: no access control
}

#[ink(message)]
pub fn good(&mut self) -> Result<()> {
    if self.env().caller() == ALLOWED_USER { // OK: Checks the caller
        self.env().terminate_contract(self.sender);
    }
}

The implementation should check the control flow in MIR, finding if there is a statement with conditional expression that uses self.env().caller() prior to the terminate_contract MIR terminator.

Reference: SWC-106