By Doug Vazquez Betting analysis and a best bet for Saturday’s light heavyweight title unification fight between the heavily favored Artur Beterbiev and Joe Smith Jr. Three of the four light heavyweight titles will be on the line inside Madison Square Garden’s Hulu Theater on Saturday night. Artur Beterbiev (-800) is a massive favorite at SI Sportsbook going into this bout against Joe Smith Jr. (+560). Beterbiev is one the most dangerous light heavyweights in recent memory, going 17-0 with a 100% win-to-knockout ratio. Smith (28-3, 22KOs), his opponent, has been very successful as of late, win…