api [nfc]: Rename StreamPostPolicy to ChannelPostPolicy

Fixes parts of zulip#631

Author: Khader-1

lib/api/model/model.dart

@@ -321,7 +321,7 @@ class ZulipStream {
   final bool historyPublicToSubscribers;
   final int? messageRetentionDays;
 
-  final StreamPostPolicy streamPostPolicy;
+  final ChannelPostPolicy streamPostPolicy;
   // final bool isAnnouncementOnly; // deprecated for `streamPostPolicy`; ignore
 
   // TODO(server-6): `canRemoveSubscribersGroupId` added in FL 142
@@ -364,14 +364,14 @@ class ZulipStream {
 /// For docs, search for "stream_post_policy"
 /// in <https://zulip.com/api/get-stream-by-id>
 @JsonEnum(valueField: 'apiValue')
-enum StreamPostPolicy {
+enum ChannelPostPolicy {
   any(apiValue: 1),
   administrators(apiValue: 2),
   fullMembers(apiValue: 3),
   moderators(apiValue: 4),
   unknown(apiValue: null);
 
-  const StreamPostPolicy({
+  const ChannelPostPolicy({
     required this.apiValue,
   });
 

lib/api/model/model.g.dart

@@ -78,7 +78,7 @@ void main() {
       'is_web_public': false,
       'history_public_to_subscribers': true,
       'message_retention_days': null,
-      'stream_post_policy': StreamPostPolicy.any.apiValue,
+      'stream_post_policy': ChannelPostPolicy.any.apiValue,
       // 'can_remove_subscribers_group': null,
       'stream_weekly_traffic': null,
     });

test/api/model/model_test.dart

@@ -171,7 +171,7 @@ ZulipStream stream({
   bool? isWebPublic,
   bool? historyPublicToSubscribers,
   int? messageRetentionDays,
-  StreamPostPolicy? streamPostPolicy,
+  ChannelPostPolicy? streamPostPolicy,
   int? canRemoveSubscribersGroup,
   int? streamWeeklyTraffic,
 }) {
@@ -186,7 +186,7 @@ ZulipStream stream({
     isWebPublic: isWebPublic ?? false,
     historyPublicToSubscribers: historyPublicToSubscribers ?? true,
     messageRetentionDays: messageRetentionDays,
-    streamPostPolicy: streamPostPolicy ?? StreamPostPolicy.any,
+    streamPostPolicy: streamPostPolicy ?? ChannelPostPolicy.any,
     canRemoveSubscribersGroup: canRemoveSubscribersGroup ?? 123,
     streamWeeklyTraffic: streamWeeklyTraffic,
   );