Replace CallAll with FuturesUnordered

Make it more consistent with the rest of the code, and make sure that
the `len()` method is available to use for tracing.

Co-authored-by: teor <teor@riseup.net>

zebra-consensus/src/transaction.rs

@@ -414,19 +414,17 @@ where
             let upgrade = request.upgrade(network);
 
             let verify_requests =
-                stream::iter((0..inputs.len()).into_iter().map(move |input_index| {
-                    script::Request {
+                (0..inputs.len()).into_iter().map(move |input_index| {
+                    let request = script::Request {
                         upgrade,
                         known_utxos: known_utxos.clone(),
                         cached_ffi_transaction: cached_ffi_transaction.clone(),
                         input_index,
-                    }
-                }));
+                    };
+                    script_verifier.clone().oneshot(request)
+                }).collect();
 
-            Ok(script_verifier
-                .call_all(verify_requests)
-                .unordered()
-                .boxed())
+            Ok(verify_requests)
         }
     }
 }