### 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)

int layout_count = GetKeyboardLayoutList(0, nullptr);
	ERR_FAIL_INDEX(p_index, layout_count);
	HKL *layouts = (HKL *)memalloc(layout_count * sizeof(HKL));
	GetKeyboardLayoutList(layout_count, layouts);
	ActivateKeyboardLayout(layouts[p_index], KLF_SETFORPROCESS);
	memfree(layouts);
}
String DisplayServerWindows::keyboard_get_layout_language(int p_index) const {
	int layout_count = GetKeyboardLayoutList(0, nullptr);
	ERR_FAIL_INDEX_V(p_index, layout_count, "");
	HKL *layouts = (HKL *)memalloc(layout_count * sizeof(HKL));
	GetKeyboardLayoutList(layout_count, layouts);
	WCHAR buf[LOCALE_NAME_MAX_LENGTH];
	memset(buf, 0, LOCALE_NAME_MAX_LENGTH * sizeof(WCHAR));
	LCIDToLocaleName(MAKELCID(LOWORD(layouts[p_index]), SORT_DEFAULT), buf, LOCALE_NAME_MAX_LENGTH, 0);
	memfree(layouts);
	return String::utf16((const char16_t *)buf).substr(0, 2);
}
Key DisplayServerWindows::keyboard_get_keycode_from_physical(Key p_keycode) const {