Fix #140342: Vulkan: Assert when quiting

When quiting Blender the timeline doesn't get updated and an assert is
triggered that the order isn't correct. The order isn't that important
anymore as the mechanism has been tested. The assert was useful during
initial development.

This PR removes the assert as it isn't valid in all cases.

source/blender/gpu/vulkan/vk_resource_pool.hh

@@ -25,8 +25,6 @@ template<typename Item> class TimelineResources : Vector<std::pair<TimelineValue
  public:
   void append_timeline(TimelineValue timeline, Item item)
   {
-    BLI_assert_msg(this->is_empty() || this->last().first <= timeline,
-                   "Timeline must be added in order");
     this->append(std::pair(timeline, item));
   }