### Godot version

v4.0.beta17.mono.official [c40020513]

### System information

Windows 11 22H2

### Issue description

If a focused subwindow is destroyed, DisplayServerWindows may still attempt to send mouse motion events to that window, because `last_focused_window` isn't updated until another window is focused.

```
ERROR: Condition "!windows.has(p_window)" is true. Returning: Point2i()
   at: window_get_position (platform/windows/display_server_windows.cpp:999)
```

### Steps to reproduce

Run the MRP, click some non-Godot application window to focus it, then click the "CLOSE" button in the secondary window. This destroys the window without re-focusing the main window, so hovering the mouse over the main window will produce the error message above.

### Minimal reproduction project

[native_windows_hover.zip](https://github.com/godotengine/godot/files/10573386/native_windows_hover.zip)

return true;
}
void DisplayServerWindows::enable_for_stealing_focus(OS::ProcessID pid) {
	_THREAD_SAFE_METHOD_
	AllowSetForegroundWindow(pid);
}
int DisplayServerWindows::keyboard_get_layout_count() const {
	return GetKeyboardLayoutList(0, nullptr);
}
int DisplayServerWindows::keyboard_get_current_layout() const {
	HKL cur_layout = GetKeyboardLayout(0);
	int layout_count = GetKeyboardLayoutList(0, nullptr);
	HKL *layouts = (HKL *)memalloc(layout_count * sizeof(HKL));
	GetKeyboardLayoutList(layout_count, layouts);
	for (int i = 0; i < layout_count; i++) {
		if (cur_layout == layouts[i]) {
			memfree(layouts);
			return i;
		}
	}
	memfree(layouts);
	return -1;
}
void DisplayServerWindows::keyboard_set_current_layout(int p_index) {