Here are the biggest calls on Wall Street on Friday: Morgan Stanley reiterates Rivian as overweight Morgan Stanley said it's standing by shares of the electric vehicle company. "As Rivian emerges from an era of acute supply chain and production challenges, investors look to see what the company can do as the units scale, pricing recalibrates and cost structure improves. While there's a lot of wood to chop, RIVN's path towards breakeven is deterministic to the equity story." Bank of America upgrades Axis Capital to buy from underperform Bank of America said in its double upgrade of the insurance and…