legacy: fix legacy code removal
- Fixes BibRank removal on d74e93c.
- Fixes WebSearch removal on 064d0ffd987. (addresses #3233)
- Fixes invenio_records externalization on 174b094a6a8.
Signed-off-by: Leonardo Rossi <leonardo.r@cern.ch>
Co-authored-by: Marco Neumann <marco@crepererum.net>