The principles of the UN Charter lay out the framework for UNSC Resolutions, and the governments of India and Pakistan both requested and accepted UNSC mediation, thereby making commitments to implement said resolutions.
Correct, and the UNSC resolutions on Kashmir and UN mediation were in fact initiated at the request of India and Pakistan and therefore meet that standard. On the other hand, one could also argue that the clause does not apply retroactively (in which case it would also invalidate the Indus Water Treaty), and therefore only applies to new disputes that come up after the Simla Agreement, such as Siachen, Sir Creek or LoC violations.