also clear pending updates from empty sections with sort tasks

Author: douira

common/src/main/java/net/caffeinemc/mods/sodium/client/render/chunk/RenderSectionManager.java

@@ -992,6 +992,7 @@ private long submitSectionTask(ChunkJobCollector collector, @NotNull RenderSecti
             if (task == null) {
                 // when a sort task is null it means the render section has no dynamic data and
                 // doesn't need to be sorted. Nothing needs to be done.
+                section.clearPendingUpdate();
                 return 0;
             }
         }