api [nfc]: Rename StreamUpdateEvent to ChannelUpdateEvent

Author: Khader-1

lib/api/model/events.dart

@@ -376,7 +376,7 @@ class ChannelDeleteEvent extends ChannelEvent {
   Map<String, dynamic> toJson() => _$ChannelDeleteEventToJson(this);
 }
 
-// TODO(#182) StreamUpdateEvent, for a [ChannelEvent] with op `update`:
+// TODO(#182) ChannelUpdateEvent, for a [ChannelEvent] with op `update`:
 //   https://zulip.com/api/get-events#stream-update
 
 /// A Zulip event of type `subscription`.

test/widgets/message_list_test.dart

@@ -414,7 +414,7 @@ void main() {
 
       testWidgets('show stream name from stream data when known', (tester) async {
         final streamBefore = eg.stream(name: 'old stream name');
-        // TODO(#182) this test would be more realistic using a StreamUpdateEvent
+        // TODO(#182) this test would be more realistic using a ChannelUpdateEvent
         final streamAfter = ZulipStream.fromJson({
           ...(deepToJson(streamBefore) as Map<String, dynamic>),
           'name': 'new stream name',