Take view archived config into account on users and posts api endpoints (#19014)

* Take view archived config into account on users and posts api endpoints

* Move the inChannel check to the top level

api4/post.go

@@ -182,6 +182,18 @@ func getPostsForChannel(c *Context, w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	if !*c.App.Config().TeamSettings.ExperimentalViewArchivedChannels {
+		channel, err := c.App.GetChannel(channelId)
+		if err != nil {
+			c.Err = err
+			return
+		}
+		if channel.DeleteAt != 0 {
+			c.Err = model.NewAppError("Api4.getPostsForChannel", "api.user.view_archived_channels.get_posts_for_channel.app_error", nil, "", http.StatusForbidden)
+			return
+		}
+	}
+
 	var list *model.PostList
 	var err *model.AppError
 	etag := ""