Background layers in legend search

[jokd]

Describe the bug
When searching the legend, background layers are presented in the result list. Maybe they should be excluded, but otherwise when clicking the layer name and turn the layer on active background layers should be turned off. The same goes for layers in an "exclusive" group.

To Reproduce
Steps to reproduce the behavior:

1. Search for a background layer
2. Turn it on
3. You have two active background layers

Expected behavior
Max one layer in an exclusive group should be active.

Desktop (please complete the following information):

• OS: Windows
• Browser Edge