Fix #145848: Crash when switching view layer after undoing ID deletion.

The root of the issue is that depsgraph relies on `ID::session_uid` to
identify and retrieve its own cached evaluation data for an ID,
including the memory for the evaluated ID data (e.g. used as keys to
retrieve IDInfo data stored in `DepsgraphNodeBuilder::id_info_hash_`).

This breaks in undo case, when a previously deleted ID is re-read from
the memfile, as it has not matching 'old' ID which address could be
reused. So while keeping its previous `session_uid`, it has a completely
new address, while the 'cow ID' retrieved from the depsgraph will still
have its `orig_id` point to the old address.

This commit fixes the issue by re-setting the `id_orig` pointer of the
`id_cow` evaluated data, when it already exists and is re-used.

This allows to keep the same `session_uid` for IDs on undo, even when
they are 're-created'. However, it is somewhat more risky than !146028.

Pull Request: https://projects.blender.org/blender/blender/pulls/146029

source/blender/depsgraph/intern/node/deg_node_id.cc

@@ -67,6 +67,13 @@ void IDNode::init_copy_on_write(Depsgraph &depsgraph, ID *id_cow_hint)
     // BLI_assert(deg_eval_copy_is_needed(id_orig));
     if (deg_eval_copy_is_needed(id_orig)) {
       id_cow = id_cow_hint;
+
+      /* While `id_cow->orig_id == id` should be `true` most of the time (a same 'orig' ID should
+       * keep a same pointer in most cases), in can happen that the same 'orig' ID got a new
+       * address, e.g. after being deleted and re-loaded from memfile undo, without any update of
+       * the depsgraph in-between (e.g. when the depsgraph belongs to an inactive viewlayer).
+       * Ref. #145848. */
+      id_cow->orig_id = this->id_orig;
     }
     else {
       id_cow = id_orig;