Node selection doesn't work properly at run-time when "Embed Subwindows" is false

### Tested versions

Reproducible in v4.6.rc2.mono.official [78c6632eb] and previous versions

### System information

Windows 11 - v4.6.rc2.mono.official [78c6632eb]

### Issue description

When the project Embed Subwindows is set to false, the selection visibility (the orange border/highlight) of child nodes/controls of windows other than the main window isn't visible where it should be, instead it's being displayed in the main window. List of selectable nodes at clicked position also doesn't work.

### Steps to reproduce

- set the project Embed Subwindows to false;
- create and add a new window to the scene tree root window;
- add some controls in the newly created window;
- run the project and select controls of the new window inside the Scene Remote tab;
- you'll see that the selection is being displayed in the main window and not in the window where the controls actually are

### Minimal reproduction project (MRP)

N/A

Reproduce the issue with Embed Subwindows disabled, a child window, and controls selected from the Scene Remote tab. Trace the runtime handling of selection visibility and the selectable-node list for non-main windows; done means both the highlight and clicked-position node list appear in the window containing the selected control.

Written by the indexing model from the issue text.