Can't color pick outside editor window in single window mode

### Tested versions

* 4.2 - works in single window mode
* 4.3 - doesn't work
* 4.4.dev - doesn't work

### System information

Windows 11 - Vulkan (Forward+)

### Issue description

The `ColorPicker`'s doesn't pick colors when the mouse is outside the editor's windows when `single_window_mode` is enabled.
It works fine when `single_window_mode` is disabled.

Bisected, regression by 385284311ab63b787448b6387e3bd046aeb15032

### Steps to reproduce

* Enable `single_window_mode` in editor settings.
* Open the picker in any exported `Color` var and use the eyedropper.
* Move the mouse outside the editor's windows. The color doesn't change.in

### Minimal reproduction project (MRP)

N/A