MM-29988 - Update exising Post APIs with collapsed threads (#16503)

app/plugin_api.go

@@ -574,7 +574,7 @@ func (api *PluginAPI) DeletePost(postId string) *model.AppError {
 }
 
 func (api *PluginAPI) GetPostThread(postId string) (*model.PostList, *model.AppError) {
-	return api.app.GetPostThread(postId, false)
+	return api.app.GetPostThread(postId, false, false, false)
 }
 
 func (api *PluginAPI) GetPost(postId string) (*model.Post, *model.AppError) {