fix: Fix OpenScreenEvent not supporting cancellation on Fabric

Author: BlayTheNinth

common/src/main/java/net/blay09/mods/balm/api/event/client/OpenScreenEvent.java

@@ -5,23 +5,23 @@
 import org.jetbrains.annotations.Nullable;
 
 public class OpenScreenEvent extends BalmEvent {
-    private Screen screen;
+    private final Screen screen;
     private Screen newScreen;
 
     public OpenScreenEvent(Screen screen) {
         this.screen = screen;
+        this.newScreen = screen;
     }
 
     public Screen getScreen() {
         return screen;
     }
 
-    public void setScreen(Screen screen) {
+    public void setScreen(@Nullable Screen screen) {
         this.newScreen = screen;
     }
 
-    @Nullable
-    public Screen getNewScreen() {
+    public @Nullable Screen getNewScreen() {
         return newScreen;
     }
 }

fabric/src/main/java/net/blay09/mods/balm/mixin/MinecraftMixin.java

@@ -30,7 +30,7 @@ public class MinecraftMixin {
     public Screen modifyScreen(Screen screen) {
         OpenScreenEvent event = new OpenScreenEvent(screen);
         Balm.getEvents().fireEvent(event);
-        return event.getNewScreen() != null ? event.getNewScreen() : screen;
+        return !event.isCanceled() ? event.getNewScreen() : null;
     }
 
     @Inject(method = "startUseItem()V", at = @At(value = "INVOKE", target = "Lnet/minecraft/client/player/LocalPlayer;getItemInHand(Lnet/minecraft/world/InteractionHand;)Lnet/minecraft/world/item/ItemStack;"), cancellable = true, locals = LocalCapture.CAPTURE_FAILSOFT)