Change default provider's loading value to true

[alanko0511]

Since OAuth and any other requests that set this loading value are executed almost instantly, setting the default value to false will make components that rely on this value flashes in the first render.

PR Checklist

• Important or complicated code is tested
• Any user facing changes are documented in the Gadget-side changelog
• Any immediate changes are slated for release in Gadget via a generated package dependency bump
• Versions within this monorepo are matching and there's a valid upgrade path

[jasong689]

Might be good to update the default value in context as well