Deprecations findings

[rikardow]

Hi, thanks for the great work on this plugin

We found a couple of deprecations in the codebase, here's the list

1. File: mod/certificate/lib.php
   Line: 386
   Message: INI directive 'magic_quotes_gpc' is deprecated since PHP 5.3 and removed since PHP 5.4.
   Type: warning

2. File: mod/certificate/locallib.php
   Line: 820
   Message: Function utf8_decode() is deprecated since PHP 8.2; Use mb_convert_encoding(), UConverter::transcode() or iconv instead.
   Type: warning

Thank you very much for your efforts