feat(ui): add support for builder to override avatars in StreamChannelAvatar.

Signed-off-by: xsahil03x <[email protected]>

packages/stream_chat_flutter/lib/src/avatars/group_avatar.dart

@@ -1,6 +1,14 @@
 import 'package:flutter/material.dart';
 import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 
+/// WidgetBuilder for [StreamGroupAvatar].
+typedef StreamGroupAvatarBuilder = Widget Function(
+  BuildContext context,
+  List<Member> members,
+  // ignore: avoid_positional_boolean_parameters
+  bool isSelected,
+);
+
 /// {@template streamGroupAvatar}
 /// Widget for constructing a group of images
 /// {@endtemplate}

packages/stream_chat_flutter/lib/src/avatars/user_avatar.dart

@@ -2,6 +2,14 @@ import 'package:cached_network_image/cached_network_image.dart';
 import 'package:flutter/material.dart';
 import 'package:stream_chat_flutter/stream_chat_flutter.dart';
 
+/// WidgetBuilder for [StreamUserAvatar].
+typedef StreamUserAvatarBuilder = Widget Function(
+  BuildContext context,
+  User user,
+  // ignore: avoid_positional_boolean_parameters
+  bool isSelected,
+);
+
 /// {@template streamUserAvatar}
 /// Displays a user's avatar.
 /// {@endtemplate}