Consider using `curl_share_init_persistent` if available

[francislavoie]

Problem Statement

PHP 8.5 added support for persistent curl handles. This means if available, the SDK can use it to reduce the overhead of reconnecting to relay/sentry for each log event or request.

Solution Brainstorm

Do a if (function_exists('curl_share_init_persistent')) around the curl setup logic to use a persistent handle, i.e. users on PHP 8.5+

https://www.php.net/manual/en/function.curl-share-init-persistent.php

[linear]

PHP-61