- Rename `find_elem` to `elem_offset` (matching `elem_exists`). - Remove unused `SDNA_StructMember` return argument. - Return an offset instead of a pointer which was being converted back into an offset by one caller, in this case there was no way to tell the difference between and element that doesn't exist and a struct member at the start of the array. Resolves UBSan warning raised in T81340.