Follow-up of https://github.com/zed-industries/zed/pull/52553

Restores previous search inputs' behavior where no extra highlights were
applied.

Before:


https://github.com/user-attachments/assets/38b6e70c-d5d5-4e06-abec-97d20af44f39

After: 


https://github.com/user-attachments/assets/6e4b3931-adf0-4c2a-afc3-f3c839fc9add


Release Notes:

- N/A