The test `test_modify_entry_invalid_fields` was hardcoding `index = 0` for TOTP entries because `add_totp` returns a URI string instead of an index.
This change unifies the index determination logic by calling `entry_manager.get_next_index()` before adding the entry. This ensures the correct index is verified for all entry types, including TOTP.
Modified:
- src/tests/test_modify_entry_validation.py: Use get_next_index() for dynamic index determination.
Co-authored-by: PR0M3TH3AN <[email protected]>