Well, Samsung eliminated the API that binding was developed to use so it’s not going to work anyway. A new binding has been developed but you’ll need to upgrade to a later OH version to use it.
It’s been many years since I last looked at OH 2.5 but assuming you tried to install this add-on through PaperUI, to stop it from trying to install it you can:
stop OH
edit $OH_USERDATA/config/org/openhab/addons.config and remove “smartthings” from the list of bindings.