### 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)

use_raw_input = true;
	RAWINPUTDEVICE rid[1] = {};
	rid[0].usUsagePage = 0x01;
	rid[0].usUsage = 0x02;
	rid[0].dwFlags = 0;
	if (p_target_window != INVALID_WINDOW_ID && windows.has(p_target_window)) {
		
		rid[0].hwndTarget = windows[p_target_window].hWnd;
	} else {
		
		rid[0].hwndTarget = 0;
	}
	if (RegisterRawInputDevices(rid, 1, sizeof(rid[0])) == FALSE) {
		
		use_raw_input = false;
	}
}
bool DisplayServerWindows::tts_is_speaking() const {
	ERR_FAIL_COND_V(!tts, false);
	return tts->is_speaking();
}
bool DisplayServerWindows::tts_is_paused() const {
	ERR_FAIL_COND_V(!tts, false);
	return tts->is_paused();
}
TypedArray<Dictionary> DisplayServerWindows::tts_get_voices() const {