### 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)

ClientToScreen(wd.hWnd, (POINT *)&r.left);
			ClientToScreen(wd.hWnd, (POINT *)&r.right);
			wd.last_pos = Point2i(r.left, r.top) - _get_screens_origin();
			wd.width = r.right - r.left;
			wd.height = r.bottom - r.top;
		} else {
			wd.last_pos = p_rect.position;
			wd.width = p_rect.size.width;
			wd.height = p_rect.size.height;
		}
		window_id_counter++;
	}
	return id;
}
bool DisplayServerWindows::wintab_available = false;
WTOpenPtr DisplayServerWindows::wintab_WTOpen = nullptr;
WTClosePtr DisplayServerWindows::wintab_WTClose = nullptr;
WTInfoPtr DisplayServerWindows::wintab_WTInfo = nullptr;
WTPacketPtr DisplayServerWindows::wintab_WTPacket = nullptr;
WTEnablePtr DisplayServerWindows::wintab_WTEnable = nullptr;
bool DisplayServerWindows::dark_title_available = false;
bool DisplayServerWindows::ux_theme_available = false;
ShouldAppsUseDarkModePtr DisplayServerWindows::ShouldAppsUseDarkMode = nullptr;
GetImmersiveColorFromColorSetExPtr DisplayServerWindows::GetImmersiveColorFromColorSetEx = nullptr;
GetImmersiveColorTypeFromNamePtr DisplayServerWindows::GetImmersiveColorTypeFromName = nullptr;
GetImmersiveUserColorSetPreferencePtr DisplayServerWindows::GetImmersiveUserColorSetPreference = nullptr;
bool DisplayServerWindows::winink_available = false;
GetPointerTypePtr DisplayServerWindows::win8p_GetPointerType = nullptr;
GetPointerPenInfoPtr DisplayServerWindows::win8p_GetPointerPenInfo = nullptr;
typedef enum _SHC_PROCESS_DPI_AWARENESS {