require-array-join-separator doesn't work with optional chaining

[WiseBird]

The rule doesn't work if join method is called with optional chaining

Rule: require-array-join-separator

        const array: string[] = ['1', '2', '3'];
        console.log(array.join());  // error
        console.log(array?.join()); // no error

[fisker]

I guess it's fine to check optional members in this rule.

[WiseBird]

Thank you