Outliner `do_item_rename` has checks so linked or overridden IDs cannot
be renamed.
A `TreeStoreElem`s ID can point to other data than "real" IDs though
(see how `outliner_add_element` casts to an ID from an arbitrary void
pointer and cases marked `/* NO ID */` in code). In those cases,
`ID_IS_LINKED` or `ID_IS_OVERRIDE_LIBRARY` _could_ return true and a the
renaming operation would fail.
Now also check if this is a real ID (`TSE_IS_REAL_ID`), so code can
continue.
Also add a proper notifier, so track renaming from the Outliner will
update the NLA immediately.
Pull Request: https://projects.blender.org/blender/blender/pulls/111110
cf43477839