Update to glycan linkage support introduced a bug in 1-6 linkages

[amjjbonvin]

Describe the bug

A wrong atom selection for the beta 1-6 linkage detection in the topoaa module caused wrong connectivity of the generated glycans.
The affected CNS file is bondglycans.cns

Expected behavior

Correct connectivity

Note that this is not present in haddock2.X as the beta 1-6 linkage was not added (yet)

[rvhonorato]

for the record: Issue was reported by a community member via our slack communication channel.