Fixups for master CI (#2118)

## Pre-launch Checklist

- [x] I read the [Flutter Style Guide] _recently_, and have followed its
advice.
- [x] I signed the [CLA].
- [x] I read the [Contributors Guide].
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-devrel
channel on [Discord].

<!-- Links -->
[Flutter Style Guide]:
https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo
[CLA]: https://cla.developers.google.com/
[Discord]: https://github.com/flutter/flutter/wiki/Chat
[Contributors Guide]:
https://github.com/flutter/samples/blob/main/CONTRIBUTING.md

code_sharing/shared/lib/src/models.g.dart

@@ -6,19 +6,21 @@ part of 'models.dart';
 // JsonSerializableGenerator
 // **************************************************************************
 
-_$_Increment _$$_IncrementFromJson(Map<String, dynamic> json) => _$_Increment(
+_$IncrementImpl _$$IncrementImplFromJson(Map<String, dynamic> json) =>
+    _$IncrementImpl(
       by: json['by'] as int,
     );
 
-Map<String, dynamic> _$$_IncrementToJson(_$_Increment instance) =>
+Map<String, dynamic> _$$IncrementImplToJson(_$IncrementImpl instance) =>
     <String, dynamic>{
       'by': instance.by,
     };
 
-_$_Count _$$_CountFromJson(Map<String, dynamic> json) => _$_Count(
+_$CountImpl _$$CountImplFromJson(Map<String, dynamic> json) => _$CountImpl(
       json['value'] as int,
     );
 
-Map<String, dynamic> _$$_CountToJson(_$_Count instance) => <String, dynamic>{
+Map<String, dynamic> _$$CountImplToJson(_$CountImpl instance) =>
+    <String, dynamic>{
       'value': instance.value,
     };