fix: focus confirm button (elastic#776)

better mimics default confirmation dialogs, and also allows the use of the escape key since the modal body becomes focused

public/components/confirm_modal/confirm_modal.js

@@ -34,6 +34,7 @@ export const ConfirmModal = props => {
         onConfirm={confirm}
         confirmButtonText={confirmButtonText}
         cancelButtonText={cancelButtonText}
+        defaultFocusedButton="confirm"
         buttonColor="danger"
       >
         {message}