Blender Git Loki

Fix T59322: View Layer - Search not working

Basically uiRNACollectionSearch->but_changed was always NULL for the
search templates. So skip_filter would always be true, and we would
never filter.

An alternative fix would be to add the following to the begin of
`template_search_add_button_searchmenu`:
```
static bool always_true = true;
template_search->search_data.but_changed = &always_true;
```