Add `showPicker()` for HtmlInputElement

[Billy-Sheppard]

Motivation

It would be useful to be able to call the showPicker() JS method from rust.

Proposed Solution

Add method for JS method showPicker() on HtmlInputElements. Should return an error if the input is unavailable or if its not of type: date, datetime-local, month, time, week, color, or file.

Alternatives

Going via an exported JS function is clunky and should be unnecessary.

Additional Context

MDN Reference here.