Embedded windows don't work properly

[IntangibleMatter]

Describe the bug
When an application creates an embedded window (a window which renders to it's own virtual "window" but actually gets drawn within another window) it opens in a new window instead of embedding it within the current window.

To Reproduce
Steps to reproduce the behavior:

1. Use Godot stable (4.5.1)
2. Create a new project, and create an empty scene
3. Make sure that within game view "embed game on next play" is enabled
4. Run the project

Expected behavior
No new window should be created, instead being contained within the editor view. Or, if "make game floating" is enabled, only one new window (which contains the options for the embedded game) should be created.

Screenshots
"embedded game window" enabled.

"embedded game window" and "floating window" enabled.

Desktop (please complete the following information):

• OS: Pop!_OS 24.04