AND NOW HERE'S THE NEWS: How's this for an odd couple--Prince and Miles Davis? Don't be surprised--now that the pair are label-mates over at Warner Bros. Records--if they don't get together on the upcoming Davis album, his first at Warners after nearly 25 years at CBS. Nothing's official yet, but as a Warners spokesman put it: "There is an ongoing musical dialogue between them, with the idea that it would be nice if this potential collaboration could come to fruition on record." . . . And yes, that was Mayor Tom Bradley appearing on the local "Video One" music-clip show (which airs weekdays at 5 p.m. on Channel 9) the other day. The mayor picked his favorite rock videos, which include Patti LaBelle's "New Attitude," Artists Against Apartheid's "Sun City," Dire Straits' "Walk of Life" and Frank Sinatra's "L.A. Is My Lady" (which was sort of a ringer, since the mayor makes a cameo appearance in the clip).