Fix array shape for errors in DatabaseQueryException

[defunctl]

Fixes the incorrect array shape for the collected Query Errors in DatabaseQueryException.

Errors look like:

object(StellarWP\Licensing\StellarWP\DB\Database\Exceptions\DatabaseQueryException)#1217 (9) {
  ["queryErrors":"StellarWP\Licensing\StellarWP\DB\Database\Exceptions\DatabaseQueryException":private]=>
  array(1) {
    ["db_delta_error"]=>
    array(1) {
      [0]=>
      string(59) "Duplicate entry 'test.com-1-5' for key 'domain_user_origin'"
    }
  }