catena -Poly[[[(2,2′-bipyridine-κ 2N , N ′)(dimethyl sulfoxide-κ O )(nitrato-κ 2O , O ′)bismuth(III)]-μ-5-carboxybenzene-1,3-dicarboxylato-κ 4O 1,O 1′:O 3,O 3′ ] dimethyl sulfoxide monosolvate]