GraphQL API modify_compute_session fails to validate duplicate names

[yomybaby]

Summary  

Currently, the GraphQL API modify_compute_session does not validate name duplication.

Steps to Reproduce  

1. Use the modify_compute_session mutation with a session name that already exists.
2. Observe that the API does not raise an error and proceeds with the modification. 
3. Check the resulting session list, which now contains duplicate names.

Expected Behavior  

The API should validate the session name to prevent duplication. An error message should be returned if a duplicate name is detected.

Actual Behavior

The API return result without validate error for the duplicated name.