[Crash]: Assertion failure in BuildRailWaypointWindow constructor when _cur_waypoint_type >= _waypoint_count

[JGRennison]

Version of OpenTTD

master

Steps to reproduce

1. Load or start a game with many NewGRF waypoint types available
2. Open the waypoint selector and select the last one
3. Abandon game
4. Load or start a game with few but not zero NewGRF waypoint types available
5. Assertion failure

bool Scrollbar::SetPosition(int): Assertion 'this->count <= this->cap ? (position == 0) : (position + this->cap <= this->count)' failed via matrix->SetClicked(_cur_waypoint_type);

Upload crash files

issue-9802.zip