Fix search field losing focus when scrolling the setting list
When scrolling the setting list, it was clearing the focus in order to close the pop-ups in the setting list. If pop-ups like for the infill pattern or extruder selection settings are not closed, the pop-up part is still rendered even if the user scrolls those settings out of view, causing the pop-up to appear somewhere on top of completely unrelated interface elements. It scrolls all the way to the top of the screen, effectively.
I couldn't find a way to cause pop-ups to be clipped with the rest of the contents of the ListView. They are always rendered on top due to the nature of the pop-up. I could find a way to trigger pop-ups to close upon changing the scrolled position without changing the focus, but that method was fairly complex with a bunch of `Connection`s and an extra signal. This is by far the simplest solution.
Contributes to issue CURA-9070.