Fix filters in covers not working (#5130)

Author: jurrejelle

src/main/java/com/gregtechceu/gtceu/api/cover/filter/FilterHandler.java

@@ -106,14 +106,14 @@ public int getSlotLimit(int slot) {
             };
 
             this.filterSlot.setFilter(this::canInsertFilterItem);
+            this.filterSlot.setOnContentsChanged(this::updateFilter);
         }
 
         return this.filterSlot;
     }
 
     public void setFilterItem(ItemStack item) {
         getFilterSlot().setStackInSlot(0, item);
-        updateFilter();
     }
 
     private void updateFilter() {

src/main/java/com/gregtechceu/gtceu/common/mui/GTMuiWidgets.java

@@ -379,10 +379,10 @@ public static <T, S extends Filter<T, S>> ParentWidget<?> createFilterRow(Flow e
         syncManager.syncValue("filterSlotHandler", filterSlotHandler);
 
         IPanelHandler panelHandler = syncManager.syncedPanel("filterPanel", true,
-                (sm, sh) -> filterHandler.loadFilter(filterSlotHandler.getSlot().getItem()).getPanel(data, sm,
-                        settings, false));
+                (sm, sh) -> filterHandler.getFilter().getPanel(data, sm, settings, false));
 
-        modSlot.changeListener((newItem, onlyAmountChanged, client, init) -> {
+        modSlot.changeListener((oldStack, newStack, client, init) -> {
+            if (init || ItemStack.isSameItem(oldStack, newStack)) return;
             panelHandler.closePanel();
             panelHandler.deleteCachedPanel();
         });