### Godot version

4.0.beta12

### System information

Windows 11, RTX 3080

### Issue description

When a Window Node is created with it's Transparent flag set to true and Project Settings --> Display --> Window --> Subwindows --> Embed Subwindows is false, the Window has a black background. By cycling the transparent flag from false and back to true again, during runtime, the window's background then becomes transparent. 

### Steps to reproduce

Attempt to create a Non-embedded Subwindow with a transparent background using the appropriate flags. 

### Minimal reproduction project

Note: this project is from Reddit user [gongpha](https://www.reddit.com/user/gongpha/) and his Reddit post [Learning a Godot 4.0 Window node](https://www.reddit.com/r/godot/comments/xr8yxn/learning_a_godot_40_window_node/)

https://github.com/gongpha/godot4-window-test
wd.last_pressure_update = 0;
		wd.last_tilt = Vector2();
		
		wd.im_himc = ImmGetContext(wd.hWnd);
		ImmReleaseContext(wd.hWnd, wd.im_himc);
		wd.im_position = Vector2();
		
		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 {