Steps to reproduce:

1. Setting MySQL tls_mode to verify_ca/full in configuration
2. Set TLS CA parameter in configuration
3. Try to retrieve MySQL data via the plugin

Result:
An error will be shown that client key/cert should be set
Expected:
Retrieve data from MySQL unless server requires client key and cert to be set.

MySQL docuemntation on ssl-mode for reference.

https://dev.mysql.com/doc/refman/8.0/en/connection-options.html#option_general_ssl-mode