fix: Adds support for JavaScript optional chaining syntax in bindings

[nicholasrice]

Pull Request

📖 Description

This PR adds detection for JavaScript's Optional chaining syntax to Observable.isVolatile(). Prior to this change, expressions that leveraged JavaScript optional chaining would not get detected as volatile, causing bindings to not update appropriately.

🎫 Issues

👩‍💻 Reviewer Notes

📑 Test Plan

✅ Checklist

General

• [ ] I have included a change request file using $ yarn change
• [ ] I have added tests for my changes.
• [ ] I have tested my changes.
• [ ] I have updated the project documentation to reflect my changes.
• [ ] I have read the CONTRIBUTING documentation and followed the standards for this project.

Component-specific

• [ ] I have added a new component
• [ ] I have modified an existing component
• [ ] I have updated the definition file
• [ ] I have updated the configuration file

⏭ Next Steps

[nicholasrice]

Probably needs some more tests for the other volatile scenarios.

@EisenbergEffect Yeah good call, added tests for the other conditions.

I did notice there is a test for && - is that necessary? won't that always access both sides of the operator?