LayerSwitcher: new LayerSwitcher, Hajk crashes when Openstreetmap is added as a background layer in map settings

[eri-blan]

Describe the bug
In the develop version from 2025-01-21; If the Openstreetmap background layer is added to a map, for instance by ticking the checkbox adding the Openstreetmap layer under map settings in admin, HAJK client crashes and produces an empty page when clicking on the arrow button (info/opacity etc.).

[Hallbergs]

@karljakoblarsson It seems like i have missed yet another bug when testing your PR :( . Would it be possible for you to take a look at this as well? LMK if you don't have time.

[karljakoblarsson]

#1583

[Hallbergs]

PR is merged and the issue should be solved now! @eri-blan