Fix biome modification for modded end biomes (#2365)

fabric-biome-api-v1/src/main/java/net/fabricmc/fabric/impl/biome/modification/BiomeModificationImpl.java

@@ -170,7 +170,8 @@ public class BiomeModificationImpl {
 
 				// Replace the Supplier to force it to rebuild on next call
 				biomeSource.indexedFeaturesSupplier = Suppliers.memoize(() -> {
-					return biomeSource.method_39525(biomeSource.biomes.stream().distinct().toList(), true);
+					// Using getBiomes to allow MixinBiomeSource to work
+					return biomeSource.method_39525(biomeSource.getBiomes().stream().distinct().toList(), true);
 				});
 			}
 

fabric-biome-api-v1/src/testmod/java/net/fabricmc/fabric/test/biome/FabricBiomeTest.java

@@ -116,7 +116,7 @@ public class FabricBiomeTest implements ModInitializer {
 		// Make sure data packs can define dynamic registry contents
 		// See #2225, #2261
 		BiomeModifications.addFeature(
-				BiomeSelectors.foundInOverworld(),
+				BiomeSelectors.foundInOverworld().or(BiomeSelectors.foundInTheEnd()),
 				GenerationStep.Feature.VEGETAL_DECORATION,
 				RegistryKey.of(Registry.PLACED_FEATURE_KEY, new Identifier(MOD_ID, "concrete_pile"))
 		);