[ObjC] log when got GRPC_QUEUE_TIMEOUT event from completion queue (#36095)

This is for the tat task app sometimes crash with "Unrecognized completion type".
However in obj-c wrapper, it is calling grpc_completion_queue_next with gpr_inf_future where it should never receive a timeout event.
This PR add a log and reschedule another grpc_completion_queue_next for a GRPC_OP_COMPLETE or GRPC_QUEUE_SHUTDOWN event, which is similar to the [gRPC C++ implementation](https://github.com/grpc/grpc/blob/v1.62.1/src/cpp/common/completion_queue_cc.cc#L80-L85)

Closes #36095

COPYBARA_INTEGRATE_REVIEW=https://github.com/grpc/grpc/pull/36095 from HannahShiSFB:no-throw-on-completion-queue-timeout e6eaf2f18a
PiperOrigin-RevId: 627524702

src/objective-c/GRPCClient/private/GRPCCore/GRPCCompletionQueue.mm

@@ -69,6 +69,9 @@ const grpc_completion_queue_attributes kCompletionQueueAttr = {
             case GRPC_QUEUE_SHUTDOWN:
               grpc_completion_queue_destroy(unmanagedQueue);
               return;
+            case GRPC_QUEUE_TIMEOUT:
+              NSLog(@"GRPC_QUEUE_TIMEOUT, success: %d, tag: %p", event.success, event.tag);
+              break;
             default:
               [NSException raise:@"Unrecognized completion type" format:@""];
           }