SC struck down the draft law (which had all sorts of loops and quotas deemed unconstitutional). Now this was expected during the legislation but the Israeli law angle is uninteresting here. politically: if someone was looking for an issue to topple the government then ding ding ding. (Haredi parties will die for this)
UTJ and Shas will be furious, but are they furious at the government or just at the courts? I'm not sure why they'd leave Netanyahu's government and provoke an early election when the government isn't the reason that the law was struck down.