Search using letters without diacritics (unaccented) doesn't show contacts containing letters with diacritics (accented) in results.

Describe the bug

When searching using letters without diacritics (unaccented) doesn't show contacts containing letters with diacritics (accented) in results.

Steps to reproduce

1. Create contact with first name "Álvaro" and save it.
2. Click on 'Search contacts' input field.
3. Put "Alvaro" or "alvaro" in the search field.
4. See the result without the contact created on step 1.
5. Enter "Álvaro" or "álvaro" in the search field.
6. See the result containing the contact created on the step 1.

Expected behavior

When I enter "alvaro" in the search field I should see contact named "Álvaro" in the search results.

Actual behavior

When I enter "alvaro" in the search field I don't see contact named "Álvaro" in the search results.

Contact version

6.0.0

Operating system

Docker 24.0.2: nextcloud:29-fpm sha256:109d5ca081279b08ecc7d1061b019d62961ae80dcdeb34e333aa930a7b97f1dd

PHP engine version

Other

Web server

Nginx

Database

PostgreSQL

Additional info

PHP 8.2.21

No source file or test is named. Start by reproducing the issue with a contact named “Álvaro” and an unaccented “Alvaro” query, then trace the contact search entry point and its PostgreSQL-backed search behavior. Done means unaccented searches return contacts containing the corresponding accented letters, while the existing reproduction steps pass.