Use y-clipping settings from the map view when creating a new scene or loading chunks from it

[leMaik]

Also fixes requiring two reloads after changing the y-clipping settings of a scene.

Closes #1741

[Peregrine05]

Things seem slightly confusing now.

Chunky appears to use the Map Y clip when Load selected chunks or New scene from selection in the Map tab context menu is used, but it uses the Scene Y clip when Load selected chunks or Reload chunks in the Scene tab is used. Additionally, changing the Map Y clip while the Scene tab is open causes the Scene Y clip values to apparently reset to their default values; however, the internal values are not changed, and the UI values are set properly once it refreshes.

I think that either there should be one set of sliders that controls both the map view and the scene clip, or there should be two separate sets of sliders, as Chunky was previously, but with a note that points users to the Scene tab to change the Scene Y clip.

As I recall, the main issue was that the Scene Y clip values were not being set properly, which resulted in portions of the world not being loaded. Users would see the Map Y clip controls, and assume that they changed the Scene Y clip, so a note next to them, I believe, would be effective.

[leMaik]

Chunky appears to use the Map Y clip when Load selected chunks or New scene from selection in the Map tab context menu is used, but it uses the Scene Y clip when Load selected chunks or Reload chunks in the Scene tab is used.

@Peregrine05 This is exactly the intended behavior. I do see that it might be confusing if you create a scene from the left panel – I didn't consider that.

Additionally, changing the Map Y clip while the Scene tab is open causes the Scene Y clip values to apparently reset to their default values; however, the internal values are not changed, and the UI values are set properly once it refreshes.

That is not supposed to happen… I'll look into this. The scene tab is supposed to represent the scene state, regardless of whatever the map view does.

Users would see the Map Y clip controls, and assume that they changed the Scene Y clip, so a note next to them, I believe, would be effective.

Users would expect that the y clip controls from the map are applied when creating a new scene – which is what this PR does. After a scene has been created, the y clip (as well as any other scene settings) can be controlled in the scene tab.

two separate sets of sliders, as Chunky was previously, but with a note that points users to the Scene tab to change the Scene Y clip.

A UI that needs a note to explain how it works is the worst solution we could find.