Handle the Unknown option for rhythm in detailed update

[nihal467]

Describe the bug

Unknown for the rhythm in the vital section of the detail log update, it's throwing error in the frontend

To Reproduce
Steps to reproduce the behavior:

1. Go to patient tab, click on any active consultation
2. click on the log update button
3. create a detailed round update
4. click on the vitals section
5. select none for the rhythm and save it
6. See error

Expected behavior

none need to be handled properly in the frontend, as we don't save the unknown in the backend for that field

Screenshots