First/last split of name creating spurious ambiguity

```py
>>> report = ''
>>> for p in anthology.people.values():
for name in p.names:
if ' ' in name.last:
# move split point one word to the left
# (note that this will be run on all names so the symmetric operation will also be covered)
l1, l2 = name.last.split(' ', 1)
for p2 in anthology.find_people((f'{name.first} {l1}', l2)):
if p2 is not p:
report += p.id + ' ' + p2.id + '\n'
>>> print('\n'.join(sorted(report.splitlines())))
```
alberto-bugarin-diz alberto-bugarin-diz/unverified
chen-cecilia-liu chen-cecilia-liu/unverified
fernando-martinez-santiago fernando-martinez-santiago-1752
jose-g-moreno/unverified jose-g-moreno
jose-g-moreno/unverified jose-g-moreno-5797
khalid-al-khatib khalid-khatib
paloma-moreda-pozo paloma-moreda-pozo-1561
pranav-narayanan-venkit-0461 pranav-narayanan-venkit
pranav-narayanan-venkit/unverified pranav-narayanan-venkit
shikhar-kumar-sarma-gu shikhar-kumar-sarma/unverified
tiago-timponi-torrent-2297 tiago-timponi-torrent
tiago-timponi-torrent/unverified tiago-timponi-torrent
william-soto-martinez william-soto-martinez-7416

These are just the splits that cause papers to appear on different author pages. There are also **649** author pages for which the name splits associated with papers on the page are inconsistent. (Change `p2 is not p` to `p2 is p` in the code above to list these; an example is https://aclanthology.org/people/leonardo-campillos-llanos/.)

At ingestion time, can we avoid this by checking for an existing name match in the database (for a verified or unverified person)?

Cf. #7558 for a similar problem due to apostrophes.