add check for source annotation property on xref axioms

[balhoff]

xrefs axioms should only be annotated with oio:source and skos values.

Related to #28404.

[sjm41]

FYI, I see 4 such examples of this error in the current ontology:

id: GO:0004764
name: shikimate 3-dehydrogenase (NADP+) activity
xref: EC:1.1.1.282 {comment="skos:broadMatch"}
(I'm fixing this one as part of #28514)

id: GO:0018423
name: protein C-terminal leucine carboxyl O-methyltransferase activity
xref: RHEA:48544 {comment="skos:narrowMatch"}

id: GO:0047224
name: acetylgalactosaminyl-O-glycosyl-glycoprotein beta-1,3-N-acetylglucosaminyltransferase activity
xref: RHEA:46884 {comment="skos:narrowMatch"}

id: GO:0051698
name: saccharopine oxidase activity
xref: RHEA:28210 {comment="skos:exactMatch"}

[pgaudet]

I fixed the 4 problematix xref types.