Linter: Unprotected DelegateCall call

[jubnzv]

The contract call that uses DelegateCall must be protected with access controls that check the address of the caller. That's important because the untrusted code called with DelegateCall can change storage values of the caller.

Examples:

#[ink(message)]
pub fn bad(&mut self, hash: Hash) {
    let selector = ink::selector_bytes!("delegatee_fn");
    let _ = build_call::<DefaultEnvironment>()
        .delegate(hash)
        .exec_input(ExecutionInput::new(Selector::new(selector)))
        .returns::<()>()
        .try_invoke(); // Bad: No access control
}

#[ink(message)]
pub fn good(&mut self, hash: Hash) {
    if self.env().caller() == ALLOWED_USER { // Good: Access control is implemented
        let selector = ink::selector_bytes!("delegatee_fn");
        let _ = build_call::<DefaultEnvironment>()
            .delegate(hash)
            .exec_input(ExecutionInput::new(Selector::new(selector)))
            .returns::<()>()
            .try_invoke();
    }
}

The implementation should check all the invocations of the created call objects in MIR. Each invocation should be preceded by the condition that uses self.env().caller() or the hash of the delegatee contract.

Reference: SWC-112

Related: #1965