minor linter fixes (#1010)

Author: Brazol

packages/stream_video/lib/src/call/state/mixins/state_lifecycle_mixin.dart

@@ -2,7 +2,6 @@ import 'package:collection/collection.dart';
 import 'package:state_notifier/state_notifier.dart';
 
 import '../../../call_state.dart';
-import '../../../errors/video_error.dart';
 import '../../../logger/impl/tagged_logger.dart';
 import '../../../models/call_member_state.dart';
 import '../../../models/call_received_data.dart';

packages/stream_video/test/src/call/call_test_helpers.dart

@@ -13,7 +13,6 @@ import 'package:stream_video/src/coordinator/models/coordinator_models.dart';
 import 'package:stream_video/src/core/client_state.dart';
 import 'package:stream_video/src/sfu/data/events/sfu_events.dart';
 import 'package:stream_video/src/sfu/data/models/sfu_call_state.dart';
-import 'package:stream_video/src/sfu/data/models/sfu_error.dart';
 import 'package:stream_video/src/sfu/data/models/sfu_participant.dart';
 import 'package:stream_video/src/shared_emitter.dart';
 import 'package:stream_video/src/state_emitter.dart';