Allow confidential submissions for logged in user

Currently when the Confidential submissions option is turn on, logged in user will be prompt to logged out and then submit the form (This form is confidential. You must Log out to submit it). This will not work in the case where you don't want to keep track of the IP but want both anonymous user and authenticated user to able to submit the form.

The proposed implementation would add a hook that allows module to alter allowed roles for confidential submission.

/**
 * Alter allowed roles confidential submission.
 *
 * @param object $node
 *   The loaded node object containing a webform.
 * @param array $allowed_roles
 *   List of allowed roles
 * @param boolean $user_is_allowed
 *   Reference to boolean to be set to whether the current user is allowed.
 */
/**
 * Alter allowed roles confidential submission.
 *
 * @param object $node
 *   The loaded node object containing a webform.
 * @param array $allowed_roles
 *   List of allowed roles
 * @param boolean $user_is_allowed
 *   Reference to boolean to be set to whether the current user is allowed.
 */
function hook_webform_confidential_allowed_roles_alter(&$allowed_roles, $node, &$user_is_allowed) {
  global $user;

  $node_allowed_roles = $node->webform['roles'];
  
  // Base allowed roles for submission on the webform_submission_access_control.
  foreach($node_allowed_roles as $rid) {
    $context['allowed_roles'][$rid] = TRUE;
  }
  if (array_intersect( array_keys($user->roles), $node_allowed_roles)) {
    $context['user_is_allowed'] = TRUE;
  }
}