You can change the loading screen type in the Game's properties. However, the Construct Splash screen is forced to be used with the free version. To remove it you must buy premium.
But since you do have premium, click the topmost object in the objects bar, which should be your game/project. Then in the properties bar, you can select how you want the game to load.
Unless this is an HTML-only issue, in which case I have no idea.