[labs/ssr] Consider other DOM shims for ARIA attr reflection during SSR

[augustjk]

Should this be an RFC?

• This is not a substantial change

Which package is this a feature request for?

SSR (@lit-labs/ssr)

Description

Context: #3677 (comment)

The ARIA attribute reflection logic in LitElementRenderer is dependent on our implementation of attachInternals() for HTMLElement in @lit-labs/ssr-dom-shim and may not work for users of other DOM shims. Currently jsdom nor happy-dom implement attachInternals() so there's nothing to support but we'll have to address this as ElementInternals gets wider adoption.

Alternatives and Workarounds

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