fix make_affiliations

[csae8092]

leaving only if end_date

not

g.add((join_uri, RDF.type, CIDOC["E85_Joining"]))
g.add((join_uri, CIDOC["P143_joined"], subj))
g.add((join_uri, CIDOC["P144_joined_with"], org_affiliation_uri))
g.add((join_uri, RDFS.label, Literal(join_label, lang=lang)))
g.add((leave_uri, RDF.type, CIDOC["E86_Leaving"]))
g.add((leave_uri, CIDOC["P145_separated"], subj))
g.add((leave_uri, CIDOC["P146_separated_from"], org_affiliation_uri))
g.add((leave_uri, RDFS.label, Literal(leave_label, lang=lang)))
begin, end = extract_begin_end(x, fill_missing=False)
if begin:
    ts_uri = URIRef(f"{join_uri}/timestamp/{begin}")
    g.add((join_uri, CIDOC["P4_has_time-span"], ts_uri))
    g += create_e52(ts_uri, begin_of_begin=begin, end_of_end=begin)
if end:
    ts_uri = URIRef(f"{leave_uri}/timestamp/{end}")
    g.add((leave_uri, CIDOC["P4_has_time-span"], ts_uri))
    g += create_e52(ts_uri, begin_of_begin=end, end_of_end=end)

but

g.add((join_uri, RDF.type, CIDOC["E85_Joining"]))
g.add((join_uri, CIDOC["P143_joined"], subj))
g.add((join_uri, CIDOC["P144_joined_with"], org_affiliation_uri))
g.add((join_uri, RDFS.label, Literal(join_label, lang=lang)))
begin, end = extract_begin_end(x, fill_missing=False)
if begin:
    ts_uri = URIRef(f"{join_uri}/timestamp/{begin}")
    g.add((join_uri, CIDOC["P4_has_time-span"], ts_uri))
    g += create_e52(ts_uri, begin_of_begin=begin, end_of_end=begin)
if end:
    ts_uri = URIRef(f"{leave_uri}/timestamp/{end}")
   g.add((leave_uri, RDF.type, CIDOC["E86_Leaving"]))
   g.add((leave_uri, CIDOC["P145_separated"], subj))
   g.add((leave_uri, CIDOC["P146_separated_from"], org_affiliation_uri))
   g.add((leave_uri, RDFS.label, Literal(leave_label, lang=lang)))
    g.add((leave_uri, CIDOC["P4_has_time-span"], ts_uri))
    g += create_e52(ts_uri, begin_of_begin=end, end_of_end=end)