[Driver][MysqliConnection] Avoid PHP fatal error with max allowed packet

Before this PR, the max allowed packet is fetched by using the native mysqli connection without using a prepared statement. This is maybe more performant but totally wrong if there is an issue with the database between the connection instanciation & the max allowed packet fetch. This can result to a PHP fatal error...

In order to handle this case, we now use a prepared statement where everything is checked.