core: recheck floating windows after monitor layout changes

[vaxerski]

Rechecks the position of floating windows after monitor layout changes.

Fixes #10030

[vaxerski]

@Kyuunex can you verify

[Kyuunex]

It no longer goes offscreen. Still buggy tho.

When I revert back to dual screen, it goes to the left screen. After that, when I switch to a different workstation on the right screen, it disappears on the left screen because it technically still belongs to the workstation that was on the right screen before switching and it isn't being displayed anymore.