expose default block size of dynamic launch config as property

src/pystencils/codegen/gpu_indexing.py

@@ -291,6 +291,10 @@ class DynamicBlockSizeLaunchConfiguration(GpuLaunchConfiguration):
     def parameters(self) -> frozenset[Parameter]:
         """Parameters of this launch configuration"""
         return self._params
+    
+    @property
+    def default_block_size(self) -> dim3:
+        return self._default_block_size
 
     @property
     def block_size(self) -> dim3 | None: