Update to php-agent 10.11.0.3 overrides mysql_mode variable

[TheoSl93]

Description

After updating to agent 10.11.0.3 some queries stopped working because the global variables were overridden. I have defined in my config that ONLY_FULL_GROUP_BY shouldn't be as variable, but the queries are executed with it, what leads to mysql fail. The workaround I found was disabling the explain flag

Steps to Reproduce

Find a way to show your sql variables in PHP, running the query SELECT @@sql_mode;, those won't be the ones you configured as global variables. Once you disable the explain flag, the real variables will be shown.

Expected Behavior

The variables set to be in the global scope have to stay the same whether the explain flag is on or off on version 10.11.0.3