Fix memory leak in cryptomatte

Since cbf033c055 the `matte_id` will be allocated in the node
storage for the forward compatibility purposes. However, this
field was never freed, leading to memory leak.

Causes annoying popup on macOS when running Cycles tests,
for example render_passes_cryptomatte_asset.blend

Differential Revision: https://developer.blender.org/D14728

source/blender/nodes/composite/nodes/node_composite_cryptomatte.cc

@@ -21,6 +21,8 @@
 #include "BKE_library.h"
 #include "BKE_main.h"
 
+#include "MEM_guardedalloc.h"
+
 #include <optional>
 
 /* -------------------------------------------------------------------- */
@@ -249,6 +251,7 @@ static void node_free_cryptomatte(bNode *node)
   NodeCryptomatte *nc = static_cast<NodeCryptomatte *>(node->storage);
 
   if (nc) {
+    MEM_SAFE_FREE(nc->matte_id);
     BLI_freelistN(&nc->runtime.layers);
     BLI_freelistN(&nc->entries);
     MEM_freeN(nc);
@@ -264,6 +267,7 @@ static void node_copy_cryptomatte(bNodeTree *UNUSED(dest_ntree),
 
   BLI_duplicatelist(&dest_nc->entries, &src_nc->entries);
   BLI_listbase_clear(&dest_nc->runtime.layers);
+  dest_nc->matte_id = static_cast<char *>(MEM_dupallocN(src_nc->matte_id));
   dest_node->storage = dest_nc;
 }