By Saeed Azhar, Noor Zainab Hussain and Niket Nishant (Reuters) -Profits slid at Wall Street’s biggest banks in the third quarter as they braced for a weaker economy while investment banking was hit hard, but investors saw a silver lining with some banks beating estimates. JPMorgan Chase & Co, Morgan Stanley, Citigroup Inc and Wells Fargo & Co’s showed a slide in net income after turbulent markets choked off investment banking activity and lenders set aside more rainy-day funds to cover losses from borrowers who fall behind on payments. “We’re in an environment where it’s kind of odd,” said JP…