Update MeSH import for 2023+ data (#151)

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Co-authored-by: Charles Tapley Hoyt <cthoyt@gmail.com>

src/pyobo/sources/mesh.py

@@ -186,7 +186,12 @@ def get_descriptor_records(element: Element, id_key: str, name_key) -> List[Dict
 
 def get_scope_note(descriptor_record) -> Optional[str]:
     """Get the scope note from the preferred concept in a term's record."""
-    for concept in descriptor_record["concepts"]:
+    if isinstance(descriptor_record, dict):
+        # necessary for pre-2023 data
+        concepts = descriptor_record["concepts"]
+    else:
+        concepts = descriptor_record
+    for concept in concepts:
         scope_note = concept.get("ScopeNote")
         if scope_note is not None:
             return scope_note.replace("\\n", "\n").strip()