groups_action_clean_up_invites_requests( $user_id,  $group_id )

function groups_action_clean_up_invites_requests( $user_id, $group_id ) {

	$invites_class = new BP_Groups_Invitation_Manager();
	// Remove invitations/requests where the deleted user is the receiver.
	$invites_class->delete( array(
		'user_id' => $user_id,
		'item_id' => $group_id,
		'type'    => 'all'
	) );
	/**
	 * Remove invitations where the deleted user is the sender.
	 * We'll use groups_uninvite_user() so that notifications will be cleaned up.
	 */
	$pending_invites = groups_get_invites( array(
		'inviter_id' => $user_id,
		'item_id'    => $group_id,
	) );

	if ( $pending_invites ) {
		foreach ( $pending_invites as $invite ) {
			groups_uninvite_user( $invite->user_id, $group_id, $user_id );
		}
	}
}