Limited borrowed types to modded

- Pack validation rejects borrowedDimensionType on platforms that generate their own Iris dimension type, with an error naming the supported loaders
- Dimension type keys and registry contracts honor borrowedDimensionType only when the platform generation registry supports borrowed types, so Bukkit always derives its generated iris type
- The Bukkit runtime contract always expects the generated Iris type; hotload still refuses a borrowedDimensionType change

adapters/modded-common/src/main/java/art/arcane/iris/modded/ModdedGenerationRegistry.java

@@ -46,6 +46,11 @@ final class ModdedGenerationRegistry implements PlatformGenerationRegistry {
         );
     }
 
+    @Override
+    public boolean supportsBorrowedDimensionTypes() {
+        return true;
+    }
+
     @Override
     public Definition definition(String registryKey, String resourceKey) {
         return nativeRegistry.definition(registryKey, resourceKey);

adapters/modded-common/src/main/java/art/arcane/iris/modded/ModdedPlatform.java

@@ -80,6 +80,11 @@ public final class ModdedPlatform implements IrisPlatform {
         return loader.platformName();
     }
 
+    @Override
+    public boolean supportsBorrowedDimensionTypes() {
+        return true;
+    }
+
     @Override
     public String minecraftVersion() {
         return loader.minecraftVersion();