Fetch schemaId on legacy cred def

acapy_agent/anoncreds/default/legacy_indy/registry.py

@@ -358,10 +358,25 @@ async def get_credential_definition(
                     {"ledger_id": ledger_id},
                 )
 
+            # Convert seqNo to schema_id if needed
+            schema_id_from_cred_def = cred_def["schemaId"]
+            if schema_id_from_cred_def.isdigit():
+                # schemaId is a seqNo, fetch the actual schema to get its ID
+                try:
+                    schema = await ledger.fetch_schema_by_seq_no(
+                        int(schema_id_from_cred_def)
+                    )
+                    if schema and schema.get("id"):
+                        schema_id_from_cred_def = schema["id"]
+                    # If schema is None or missing id, fall back to seqNo
+                except LedgerError:
+                    # If fetching fails, fall back to using seqNo as schemaId
+                    pass
+
             cred_def_value = CredDefValue.deserialize(cred_def["value"])
             anoncreds_credential_definition = CredDef(
                 issuer_id=cred_def["id"].split(":")[0],
-                schema_id=cred_def["schemaId"],
+                schema_id=schema_id_from_cred_def,
                 type=cred_def["type"],
                 tag=cred_def["tag"],
                 value=cred_def_value,