Article details or errors in JSTOR and VitalSource picker not announced to screen readers immediately

In the JSTOR and VitalSource content pickers, when the user enters an article ID or book ID and presses enter or clicks the button, we fetch metadata for that article and display a title and thumbnail.

If there is an error, we mark the input field as invalid using `aria-invalid` and link the error using `aria-describedby`. If the user causes the control to be described again by navigating away from it and back, or pressing the button to describe the focused control, they will hear the error. However at the point when article detail fetch finishes, either successfully or with an error, nothing is immediately announced, as there is no `aria-live` region.

With a standard HTML form what would happen next is that the user tries to submit the form, and then the browser would focus the input with an error and report the validation issue. Since we disable the submit button however, that won't happen.