Hi,
The only registration form I see on your website is the one from the top module with a popup:
monosnap.com/file/e045T7yagW2yqY1CMJ0sccyvoD9mYX
That form doesn't come from HikaShop, and I don't know why it goes to the user control panel page of HikaShop after the registration.
You would have to ask that to the developer of that registration form. Maybe the module has a setting where you can enter the target URL after the registration ? Or maybe it would require some modification somewhere in that module ?
Normally, with the normal HikaShop registration form, after the registration process is done, the "Thank you for registering" message is displayed on the page index.php?option=com_hikashop&ctrl=user&task=after_register of HikaShop which is blank.