If for some reason you require to uninstall OSLC Connect for Confluence from your Confluence instance, you just need to follow the official documentation as for any other plugin.

On the removal, or expiration of the license, Collaboration Links between Confluence and the OSLC Remote Application remain present in the system. Collaboration Links from Confluence to the OSLC Remote Application will no longer provide rich hovers or real-time retrieval of updates or icons. Removing Collaboration Links after uninstalling the connector is still possible.