[Bug] iconv() notice in PHP GeoIp2 LocationProvider during fuzzy matching

[diosmosis]

What happened?

A Matomo for WordPress user reports seeing these notices in their PHP error log:

iconv(): Detected an illegal character in input string in /var/www/example.com/htdocs/wp-content/plugins/matomo/app/plugins/GeoIp2/LocationProvider/GeoIp2/Php.php on line 296;

(source: https://wordpress.org/support/topic/php-errors-in-server-log/)

What should happen?

Notices should not be emitted by the PHP GeoIP location provider. The fuzzyMatch method should perhaps ignore characters that cannot be transliterated or errors should be silenced.

How can this be reproduced?

Unknown, though the user in question is using the default DB-IP databases, and geolocation appears to be working (there is data in the Locations reports).

Matomo version

5.1.0

PHP version

No response

Server operating system

No response

What browsers are you seeing the problem on?

No response

Computer operating system

No response

Relevant log output

No response

Validations

• [X] Read our Contributing Guidelines.
• [X] Follow our Security Policy.
• [X] Check that there isn't already an issue that reports the same bug to avoid creating duplicates.
• [X] The provided steps to reproduce is a minimal reproducible of the Bug.