Evidence for the Intervention of Different C−H Activating Intermediates in the Irradiation of (η 5 -C 5 Me 5 )(PMe 3 )IrH 2 and the Reaction of (η 5 -C 5 Me 5 )(PMe 3 )Ir(H)(Cl) with Strong Base. Detection and Spectroscopic Characterization of (η 5 -C 5 Me 5 )(PMe 3 )Ir(Li)(Cl), an Intermediate in the Dehydrohalogenation Reaction