parser yang UPDATE automatic parsing of nested extensions

Fixes #2265
diff --git a/src/tree_schema_free.c b/src/tree_schema_free.c
index 91ba72b..ee05d3c 100644
--- a/src/tree_schema_free.c
+++ b/src/tree_schema_free.c
@@ -80,6 +80,8 @@
     LY_LIST_FOR_SAFE(ext->child, next, stmt) {
         lysp_stmt_free(ctx->ctx, stmt);
     }
+
+    FREE_ARRAY(ctx, ext->exts, lysp_ext_instance_free);
 }
 
 /**