Update "Textfield" to most recent Spectrum CSS beta

[Westbrook]

Expected Behaviour

Textfield meets the most recent Spectrum CSS specification

Actual Behaviour

Beta releases of this pattern have breaking changes.

block #477

Proposal

Re-implement this pattern with @spectrum-css/[email protected].

Considerations:

• The beta releases rely on [dir="rtl"] selectors, the CSS for which needs to be processed differently than previously. This also requires some affordance in the JS to acquire dir from an ancestor element. The easiest approach here would be to leverage document.dir but it's technically possible to have multiple dir values across a document. Should we resolve this value to the "closest" instance or to the "root" instance? Either seems acceptable if we document it and allow it to be locally set.
• order of selector writing can cause processing errors where [dir=ltr] .spectrum-Textfield--quiet.spectrum-Textfield.is-invalid .spectrum-Textfield-validationIcon becomes :host([quiet][invalid]) .spectrum-Textfield[dir='ltr'] .icon due to expectations in our processing
• uses .is-focused and .is-keyboard focused as opposed to :focus and :focus-visible so we'll need to manage those values (possibly not that big of a deal being these selectors ALWAYS duplicate an input:focus selector that matches it for appropriately to our current approach)