re-re-enable lint unnecessary_const (#20103)

diff --git a/examples/platform_channel/lib/main.dart b/examples/platform_channel/lib/main.dart
index 69c1f81..41129cc 100644
--- a/examples/platform_channel/lib/main.dart
+++ b/examples/platform_channel/lib/main.dart
@@ -14,9 +14,9 @@
 
 class _PlatformChannelState extends State<PlatformChannel> {
   static const MethodChannel methodChannel =
-      const MethodChannel('samples.flutter.io/battery');
+      MethodChannel('samples.flutter.io/battery');
   static const EventChannel eventChannel =
-      const EventChannel('samples.flutter.io/charging');
+      EventChannel('samples.flutter.io/charging');
 
   String _batteryLevel = 'Battery level: unknown.';
   String _chargingStatus = 'Battery status: unknown.';