chore: Make code tidy.

Author: cloudwebrtc

lib/src/native/factory_impl.dart

@@ -51,7 +51,6 @@ class RTCFactoryNative extends RTCFactory {
     return MediaRecorderNative();
   }
 
-  @override
   VideoRenderer videoRenderer() {
     return RTCVideoRenderer();
   }

lib/src/web/rtc_video_renderer_impl.dart

@@ -3,11 +3,10 @@ import 'dart:html' as html;
 import 'dart:js_util' as jsutil;
 import 'dart:ui' as ui;
 
-import 'package:flutter/foundation.dart';
-import 'package:flutter/services.dart';
-
 import 'package:dart_webrtc/dart_webrtc.dart';
 import 'package:dart_webrtc/src/media_stream_impl.dart';
+import 'package:flutter/foundation.dart';
+import 'package:flutter/services.dart';
 import 'package:webrtc_interface/webrtc_interface.dart';
 
 // An error code value to error name Map.

lib/src/web/rtc_video_view_impl.dart

@@ -1,9 +1,8 @@
 import 'dart:async';
 import 'dart:math';
 
-import 'package:flutter/material.dart';
-
 import 'package:dart_webrtc/dart_webrtc.dart';
+import 'package:flutter/material.dart';
 import 'package:webrtc_interface/webrtc_interface.dart';
 
 import 'rtc_video_renderer_impl.dart';