Fix Phone Input error in Internet Explorer

[aduth]

Why: HTMLSelectElement#selectedOptions is not supported in Internet Explorer.

See: https://developer.mozilla.org/en-US/docs/Web/API/HTMLSelectElement/selectedOptions#browser_compatibility

NewRelic: https://onenr.io/0xZw0LMvpwv

[aduth]

As far as testing this for continuous integration, it'd be nice if there could be some way to hook into TypeScript's awareness of the DOM APIs to flag unsupported properties like this. Alternatively, in the past we've done similar with things like Event vs. CustomEvent, but it's very ad-hoc, and not very scalable for as much of the unsupported properties we'd have to consider. It's also worth weighing just how much longer we'd need to support IE11 at all 🤷

[zachmargolis]

As far as testing this for continuous integration, it'd be nice if there could be some way to hook into TypeScript's awareness of the DOM APIs to flag unsupported properties like this

the irony that TypeScript is a Microsoft project 😭

[zachmargolis]

LGTM