obtains staked-nodes from the root-bank (#14257)

... as opposed to the working bank

core/src/rpc.rs

@@ -187,7 +187,7 @@ impl JsonRpcRequestProcessor {
                 "Bank with {:?} not found at slot: {:?}",
                 commitment_level, slot
             );
-            r_bank_forks.root_bank().clone()
+            r_bank_forks.root_bank()
         })
     }