fix(contract):change required field to optional in detail

app/repositories/register_status.py

@@ -11,7 +11,7 @@ class RegisterStatusRepository(BaseRepository):
 
     async def get_last(self,project_id:uuid.UUID):
         last = await use_collection(TaskEnv.CLN_AUDIT_STATUS).find({"project_id":project_id}).sort('$natural', -1).to_list(1)
-        if last:
+        if last and len(last) > 0 and 'number' in last[0]:
             return last[0]['number']
         else:
             return None