fix: clear stale external auth validation error after revalidation - #28881

Fixes #28876

On /settings/external-auth, a row could show a disabled Authenticated button next to Error: token failed to validate, and a "Test Validate" run would toast Application link is valid. while the error text stayed until a hard reload.

The badge and the error come from two react-query entries that were never resynced. The button reads the per-provider query, but validate_error only exists on the list query, and validateExternalAuth only wrote the per-provider cache key. Nothing except unlink ever invalidated the list, so an error captured at page load stuck around after a successful re-auth or validation.

Two changes:

• validateExternalAuth.onSuccess now also invalidates the list query (exact key), so the refetched link reflects current state.
• The error text no longer renders on a row that resolves to authenticated, so a transient disagreement between the two endpoints (list validates via refresh with retry, by-ID validates directly) can't show the contradiction either.

Added tests covering both: one drives "Test Validate" from a failed state and asserts the list is refetched and the error clears, one pins that a stale list error never renders next to an Authenticated button. Both fail without the fix. Also set authenticated: false on the Failed storybook story, since a failed-validation link is unauthenticated.

Verification:

Test Files  1 passed (1)
     Tests  2 passed (2)

biome check and tsc -p . clean; the existing device-flow test in pages/ExternalAuthPage still passes.

Written with AI assistance.